Update more external links (#18819)

LICENSE

                     GNU GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007
 
- Copyright (c) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Copyright (c) 2007 Free Software Foundation, Inc. <https://www.fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
 may consider it more useful to permit linking proprietary applications with
 the library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.  But first, please read
-<https://www.gnu.org/philosophy/why-not-lgpl.html>.
-
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

Marlin/src/HAL/DUE/HAL.cpp

  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
  */
 
 /**

Marlin/src/HAL/ESP32/ota.cpp

  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
  */
 
 #ifdef ARDUINO_ARCH_ESP32

Marlin/src/HAL/STM32/SoftwareSerial.cpp

  *
  * Multi-instance software serial library for Arduino/Wiring
  * -- Interrupt-driven receive and other improvements by ladyada
- *    (https://ladyada.net)
+ *    <https://ladyada.net>
  * -- Tuning, circular buffer, derivation from class Print/Stream,
  *    multi-instance support, porting to 8MHz processors,
  *    various optimizations, PROGMEM delay tables, inverse logic and
- *    direct port writing by Mikal Hart (http://www.arduiniana.org)
- * -- Pin change interrupt macros by Paul Stoffregen (https://www.pjrc.com)
- * -- 20MHz processor support by Garrett Mace (http://www.macetech.com)
- * -- ATmega1280/2560 support by Brett Hagman (https://www.roguerobotics.com/)
+ *    direct port writing by Mikal Hart <http://www.arduiniana.org>
+ * -- Pin change interrupt macros by Paul Stoffregen <https://www.pjrc.com>
+ * -- 20MHz processor support by Garrett Mace <http://www.macetech.com>
+ * -- ATmega1280/2560 support by Brett Hagman <https://www.roguerobotics.com>
  * -- STM32 support by Armin van der Togt
  *
  * This library is free software; you can redistribute it and/or

Marlin/src/HAL/shared/backtrace/unwarmbytab.cpp

  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ * file, You can obtain one at https://www.mozilla.org/en-US/MPL/2.0/
  *
  * This library was modified, some bugs fixed, stack address validated
  * and adapted to be used in Marlin 3D printer firmware as backtracer

Marlin/src/feature/dac/dac_mcp4728.cpp

  * https://ww1.microchip.com/downloads/en/DeviceDoc/22187a.pdf
  *
  * For discussion and feedback, please go to:
- * https://arduino.cc/forum/index.php/topic,51842.0.html
+ * https://forum.arduino.cc/index.php/topic,51842.0.html
  */
 
 #include "../../inc/MarlinConfig.h"

Marlin/src/gcode/motion/G5.cpp

 
 /**
  * Parameters interpreted according to:
- * https://linuxcnc.org/docs/2.6/html/gcode/gcode.html#sec:G5-Cubic-Spline
+ * https://linuxcnc.org/docs/2.7/html/gcode/g-code.html#gcode:g5
  * However I, J omission is not supported at this point; all
  * parameters can be omitted and default to zero.
  */

buildroot/share/vscode/avrdude.conf

 #     VCC pins are not defined for the programmer, a message
 #     indicating that the device needs a power-cycle is printed out.
 #     This flag was added to work around a problem with the
-#     at90s4433/2333's; see the at90s4433 errata at:
+#     at90s4433/2333's; see the at90s4433 errata page 2 at:
 #
-#         http://www.atmel.com/atmel/acrobat/doc1280.pdf
+#         https://ww1.microchip.com/downloads/en/AppNotes/doc2574.pdf
 #
 # INSTRUCTION FORMATS
 #
 
 programmer
   id    = "usbasp";
-  desc  = "USBasp, http://www.fischl.de/usbasp/";
+  desc  = "USBasp, https://www.fischl.de/usbasp/";
   type  = usbasp;
 ;
 
 programmer
   id    = "usbtiny";
-  desc  = "USBtiny simple USB programmer, http://www.ladyada.net/make/usbtinyisp/";
+  desc  = "USBtiny simple USB programmer, https://learn.adafruit.com/usbtinyisp";
   type  = usbtiny;
 ;
 
 
 programmer
   id    = "bsd";
-  desc  = "Brian Dean's Programmer, http://www.bsdhome.com/avrdude/";
+  desc  = "Brian Dean's Programmer, https://savannah.nongnu.org/projects/avrdude";
   type  = par;
   vcc   = 2, 3, 4, 5;
   reset = 7;
 
 programmer
   id    = "atisp";
-  desc  = "AT-ISP V1.1 programming cable for AVR-SDK1 from <http://micro-research.co.th/> micro-research.co.th";
+  desc  = "AT-ISP V1.1 programming cable for AVR-SDK1 from <https://www.micro-research.co.th/> micro-research.co.th";
   type  = par;
   reset = ~6;
   sck   = ~8;
 ;
 
 # It is almost same as pony-stk200, except vcc on pin 5 to auto
-# disconnect port (download on http://electropol.free.fr)
+# disconnect port download on http://www.electropol.fr
 programmer
   id    = "frank-stk200";
   desc  = "Frank STK200";
 ;
 
 # The AT98ISP Cable is a simple parallel dongle for AT89 family.
-# http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2877
+# https://www.microchip.com/wwwAppNotes/AppNotes.aspx?appnote=en592141
 programmer
 id = "89isp";
 desc = "Atmel at89isp cable";

buildroot/share/vscode/avrdude_linux.conf

 #     VCC pins are not defined for the programmer, a message
 #     indicating that the device needs a power-cycle is printed out.
 #     This flag was added to work around a problem with the
-#     at90s4433/2333's; see the at90s4433 errata at:
+#     at90s4433/2333's; see the at90s4433 errata page 2 at:
 #
-#         http://www.atmel.com/atmel/acrobat/doc1280.pdf
+#         https://ww1.microchip.com/downloads/en/AppNotes/doc2574.pdf
 #
 # INSTRUCTION FORMATS
 #
 
 programmer
   id    = "usbasp";
-  desc  = "USBasp, http://www.fischl.de/usbasp/";
+  desc  = "USBasp, https://www.fischl.de/usbasp/";
   type  = usbasp;
 ;
 
 programmer
   id    = "usbtiny";
-  desc  = "USBtiny simple USB programmer, http://www.ladyada.net/make/usbtinyisp/";
+  desc  = "USBtiny simple USB programmer, https://learn.adafruit.com/usbtinyisp";
   type  = usbtiny;
 ;
 
 
 programmer
   id    = "bsd";
-  desc  = "Brian Dean's Programmer, http://www.bsdhome.com/avrdude/";
+  desc  = "Brian Dean's Programmer, https://savannah.nongnu.org/projects/avrdude";
   type  = par;
   vcc   = 2, 3, 4, 5;
   reset = 7;
 
 programmer
   id    = "atisp";
-  desc  = "AT-ISP V1.1 programming cable for AVR-SDK1 from <http://micro-research.co.th/> micro-research.co.th";
+  desc  = "AT-ISP V1.1 programming cable for AVR-SDK1 from <https://www.micro-research.co.th/> micro-research.co.th";
   type  = par;
   reset = ~6;
   sck   = ~8;
 ;
 
 # It is almost same as pony-stk200, except vcc on pin 5 to auto
-# disconnect port (download on http://electropol.free.fr)
+# disconnect port download on http://www.electropol.fr
 programmer
   id    = "frank-stk200";
   desc  = "Frank STK200";
 ;
 
 # The AT98ISP Cable is a simple parallel dongle for AT89 family.
-# http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2877
+# https://www.microchip.com/wwwAppNotes/AppNotes.aspx?appnote=en592141
 programmer
 id = "89isp";
 desc = "Atmel at89isp cable";

buildroot/share/vscode/avrdude_macOS.conf

 #     VCC pins are not defined for the programmer, a message
 #     indicating that the device needs a power-cycle is printed out.
 #     This flag was added to work around a problem with the
-#     at90s4433/2333's; see the at90s4433 errata at:
+#     at90s4433/2333's; see the at90s4433 errata page 2 at:
 #
-#         http://www.atmel.com/atmel/acrobat/doc1280.pdf
+#         https://ww1.microchip.com/downloads/en/AppNotes/doc2574.pdf
 #
 # INSTRUCTION FORMATS
 #
 
 programmer
   id    = "usbasp";
-  desc  = "USBasp, http://www.fischl.de/usbasp/";
+  desc  = "USBasp, https://www.fischl.de/usbasp/";
   type  = usbasp;
 ;
 
 programmer
   id    = "usbtiny";
-  desc  = "USBtiny simple USB programmer, http://www.ladyada.net/make/usbtinyisp/";
+  desc  = "USBtiny simple USB programmer, https://learn.adafruit.com/usbtinyisp";
   type  = usbtiny;
 ;
 

platformio.ini

 #
 # For detailed documentation with EXAMPLES:
 #
-# https://docs.platformio.org/en/latest/projectconf.html
+# https://docs.platformio.org/en/latest/projectconf/index.html
 #
 
 # Automatic targets - enable auto-uploading