Optimize some serial strings

Marlin/src/feature/I2CPositionEncoder.cpp

 
           SERIAL_ECHOPGM("New position reads as ");
           SERIAL_ECHO(get_position());
-          SERIAL_ECHOPGM("(");
+          SERIAL_CHAR('(');
           SERIAL_ECHO(mm_from_count(get_position()));
           SERIAL_ECHOLNPGM(")");
         #endif

Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp

           d = t + normal.z * z1;
           SERIAL_ECHOPGM("D from 1st point: ");
           SERIAL_ECHO_F(d, 6);
-          SERIAL_ECHO("   Z error: ");
+          SERIAL_ECHOPGM("   Z error: ");
           SERIAL_ECHO_F(normal.z*z1-get_z_correction(UBL_PROBE_PT_1_X, UBL_PROBE_PT_1_Y),6);
           SERIAL_EOL();
 
           SERIAL_EOL();
           SERIAL_ECHOPGM("D from 2nd point: ");
           SERIAL_ECHO_F(d, 6);
-          SERIAL_ECHO("   Z error: ");
+          SERIAL_ECHOPGM("   Z error: ");
           SERIAL_ECHO_F(normal.z*z2-get_z_correction(UBL_PROBE_PT_2_X, UBL_PROBE_PT_2_Y),6);
           SERIAL_EOL();
 
           d = t + normal.z * z3;
           SERIAL_ECHOPGM("D from 3rd point: ");
           SERIAL_ECHO_F(d, 6);
-          SERIAL_ECHO("   Z error: ");
+          SERIAL_ECHOPGM("   Z error: ");
           SERIAL_ECHO_F(normal.z*z3-get_z_correction(UBL_PROBE_PT_3_X, UBL_PROBE_PT_3_Y),6);
           SERIAL_EOL();
 
 
           SERIAL_ECHOPAIR("   Z error: (", Z_SAFE_HOMING_X_POINT );
           SERIAL_ECHOPAIR(",", Z_SAFE_HOMING_Y_POINT );
-          SERIAL_ECHO(") = ");
+          SERIAL_ECHOPGM(") = ");
           SERIAL_ECHO_F( get_z_correction(Z_SAFE_HOMING_X_POINT, Z_SAFE_HOMING_Y_POINT),6);
           SERIAL_EOL();
 */

Marlin/src/gcode/calibrate/M852.cpp

 
   if (!ijk) {
     SERIAL_ECHO_START();
-    SERIAL_ECHO(MSG_SKEW_FACTOR " XY: ");
+    SERIAL_ECHOPGM(MSG_SKEW_FACTOR " XY: ");
     SERIAL_ECHO_F(planner.xy_skew_factor, 6);
     SERIAL_EOL();
     #if ENABLED(SKEW_CORRECTION_FOR_Z)

Marlin/src/gcode/parser.cpp

     SERIAL_ECHO(codenum);
     SERIAL_ECHOLNPGM(")");
     #if ENABLED(FASTER_GCODE_PARSER)
-      SERIAL_ECHO(" args: \"");
+      SERIAL_ECHOPGM(" args: \"");
       for (char c = 'A'; c <= 'Z'; ++c)
         if (seen(c)) { SERIAL_CHAR(c); SERIAL_CHAR(' '); }
     #else
       SERIAL_ECHOPAIR(" args: \"", command_args);
     #endif
-    SERIAL_ECHOPGM("\"");
+    SERIAL_CHAR('"');
     if (string_arg) {
       SERIAL_ECHOPGM(" string: \"");
       SERIAL_ECHO(string_arg);

Marlin/src/module/configuration_store.cpp

       }
       CONFIG_ECHO_START;
       #if ENABLED(SKEW_CORRECTION_FOR_Z)
-        SERIAL_ECHO_P(port, "  M852 I");
+        SERIAL_ECHOPGM_P(port, "  M852 I");
         SERIAL_ECHO_F_P(port, LINEAR_UNIT(planner.xy_skew_factor), 6);
         SERIAL_ECHOPGM_P(port, " J");
         SERIAL_ECHO_F_P(port, LINEAR_UNIT(planner.xz_skew_factor), 6);
         SERIAL_ECHO_F_P(port, LINEAR_UNIT(planner.yz_skew_factor), 6);
         SERIAL_EOL_P(port);
        #else
-        SERIAL_ECHO_P(port, "  M852 S");
+        SERIAL_ECHOPGM_P(port, "  M852 S");
         SERIAL_ECHO_F_P(port, LINEAR_UNIT(planner.xy_skew_factor), 6);
         SERIAL_EOL_P(port);
       #endif
         SERIAL_ECHOLNPGM_P(port, "Stepper driver current:");
       }
       CONFIG_ECHO_START;
-      SERIAL_ECHO_P(port, "  M906");
+      SERIAL_ECHOPGM_P(port, "  M906");
       #if ENABLED(X_IS_TMC2130) || ENABLED(X_IS_TMC2208)
         SERIAL_ECHOPAIR_P(port, " X ", stepperX.getCurrent());
       #endif
         SERIAL_ECHOLNPGM_P(port, "Sensorless homing threshold:");
       }
       CONFIG_ECHO_START;
-      SERIAL_ECHO_P(port, "  M914");
+      SERIAL_ECHOPGM_P(port, "  M914");
       #if ENABLED(X_IS_TMC2130)
         SERIAL_ECHOPAIR_P(port, " X", stepperX.sgt());
       #endif

Marlin/src/module/printcounter.cpp

 
   SERIAL_ECHOPGM("Filament used: ");
   SERIAL_ECHO(this->data.filamentUsed / 1000);
-  SERIAL_ECHOPGM("m");
+  SERIAL_CHAR('m');
 
   SERIAL_EOL();
 }