Use PSTR for common labels

Marlin/src/MarlinCore.cpp

            SP_X_STR[] PROGMEM = " X",
            SP_Y_STR[] PROGMEM = " Y",
            SP_Z_STR[] PROGMEM = " Z",
-           SP_E_STR[] PROGMEM = " E";
+           SP_E_STR[] PROGMEM = " E",
+              X_LBL[] PROGMEM =  "X:",
+              Y_LBL[] PROGMEM =  "Y:",
+              Z_LBL[] PROGMEM =  "Z:",
+              E_LBL[] PROGMEM =  "E:",
+           SP_X_LBL[] PROGMEM = " X:",
+           SP_Y_LBL[] PROGMEM = " Y:",
+           SP_Z_LBL[] PROGMEM = " Z:",
+           SP_E_LBL[] PROGMEM = " E:";
 
 bool Running = true;
 

Marlin/src/MarlinCore.h

 #endif
 
 extern const char NUL_STR[], M112_KILL_STR[], G28_STR[], M21_STR[], M23_STR[], M24_STR[],
-                  SP_P_STR[], SP_T_STR[], SP_X_STR[], SP_Y_STR[], SP_Z_STR[], SP_E_STR[];
+                  SP_P_STR[], SP_T_STR[], SP_X_STR[], SP_Y_STR[], SP_Z_STR[], SP_E_STR[],
+                  X_LBL[], Y_LBL[], Z_LBL[], E_LBL[], SP_X_LBL[], SP_Y_LBL[], SP_Z_LBL[], SP_E_LBL[];
+

Marlin/src/feature/dac/stepper_dac.cpp

 
   SERIAL_ECHO_MSG("Stepper current values in % (Amps):");
   SERIAL_ECHO_START();
-  SERIAL_ECHOLNPAIR(
-    " X:", dac_perc(X_AXIS), " (", dac_amps(X_AXIS), ")"
-    " Y:", dac_perc(Y_AXIS), " (", dac_amps(Y_AXIS), ")"
-    " Z:", dac_perc(Z_AXIS), " (", dac_amps(Z_AXIS), ")"
-    " E:", dac_perc(E_AXIS), " (", dac_amps(E_AXIS), ")"
+  SERIAL_ECHOLNPAIR_P(
+    SP_X_LBL, dac_perc(X_AXIS), PSTR(" ("), dac_amps(X_AXIS), PSTR(")")
+    SP_Y_LBL, dac_perc(Y_AXIS), PSTR(" ("), dac_amps(Y_AXIS), PSTR(")")
+    SP_Z_LBL, dac_perc(Z_AXIS), PSTR(" ("), dac_amps(Z_AXIS), PSTR(")")
+    SP_E_LBL, dac_perc(E_AXIS), PSTR(" ("), dac_amps(E_AXIS), PSTR(")")
   );
 }
 

Marlin/src/lcd/HD44780/ultralcd_HD44780.cpp

         #define _LCD_W_POS 12
         #define _PLOT_X 1
         #define _MAP_X 3
-        #define _LABEL(C,X,Y) lcd_put_u8str(X, Y, C)
-        #define _XLABEL(X,Y) _LABEL("X:",X,Y)
-        #define _YLABEL(X,Y) _LABEL("Y:",X,Y)
-        #define _ZLABEL(X,Y) _LABEL("Z:",X,Y)
+        #define _LABEL(C,X,Y) lcd_put_u8str_P(X, Y, C)
+        #define _XLABEL(X,Y) _LABEL(X_LBL,X,Y)
+        #define _YLABEL(X,Y) _LABEL(Y_LBL,X,Y)
+        #define _ZLABEL(X,Y) _LABEL(Z_LBL,X,Y)
       #else
         #define _LCD_W_POS 8
         #define _PLOT_X 0

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

           }
         }
         else if (progress_state == 2 && estimation_string[0]) {
-          lcd_put_u8str(PROGRESS_BAR_X, EXTRAS_BASELINE, "R:");
+          lcd_put_u8str_P(PROGRESS_BAR_X, EXTRAS_BASELINE, PSTR("R:"));
           lcd_put_u8str(estimation_x_pos, EXTRAS_BASELINE, estimation_string);
         }
         else if (elapsed_string[0]) {
-          lcd_put_u8str(PROGRESS_BAR_X, EXTRAS_BASELINE, "E:");
+          lcd_put_u8str_P(PROGRESS_BAR_X, EXTRAS_BASELINE, E_LBL);
           lcd_put_u8str(elapsed_x_pos, EXTRAS_BASELINE, elapsed_string);
         }
 

Marlin/src/lcd/dogm/ultralcd_DOGM.cpp

       if (PAGE_UNDER(7)) {
         const xy_pos_t pos = { ubl.mesh_index_to_xpos(x_plot), ubl.mesh_index_to_ypos(y_plot) },
                        lpos = pos.asLogical();
-        lcd_put_u8str(5, 7, "X:");
+        lcd_put_u8str_P(5, 7, X_LBL);
         lcd_put_u8str(ftostr52(lpos.x));
-        lcd_put_u8str(74, 7, "Y:");
+        lcd_put_u8str_P(74, 7, Y_LBL);
         lcd_put_u8str(ftostr52(lpos.y));
       }
 
         lcd_put_wchar(')');
 
         // Show the location value
-        lcd_put_u8str(74, LCD_PIXEL_HEIGHT, "Z:");
+        lcd_put_u8str_P(74, LCD_PIXEL_HEIGHT, Z_LBL);
         if (!isnan(ubl.z_values[x_plot][y_plot]))
           lcd_put_u8str(ftostr43sign(ubl.z_values[x_plot][y_plot]));
         else

Marlin/src/module/planner.cpp

       SERIAL_ECHOPAIR("->", target.a);
       SERIAL_ECHOPAIR(") B:", b);
     #else
-      SERIAL_ECHOPAIR(" X:", a);
+      SERIAL_ECHOPAIR_P(SP_X_LBL, a);
       SERIAL_ECHOPAIR(" (", position.x);
       SERIAL_ECHOPAIR("->", target.x);
-      SERIAL_ECHOPAIR(") Y:", b);
+      SERIAL_CHAR(')');
+      SERIAL_ECHOPAIR_P(SP_Y_LBL, b);
     #endif
     SERIAL_ECHOPAIR(" (", position.y);
     SERIAL_ECHOPAIR("->", target.y);
     #if ENABLED(DELTA)
       SERIAL_ECHOPAIR(") C:", c);
     #else
-      SERIAL_ECHOPAIR(") Z:", c);
+      SERIAL_CHAR(')');
+      SERIAL_ECHOPAIR_P(SP_Z_LBL, c);
     #endif
     SERIAL_ECHOPAIR(" (", position.z);
     SERIAL_ECHOPAIR("->", target.z);
-    SERIAL_ECHOPAIR(") E:", e);
+    SERIAL_CHAR(')');
+    SERIAL_ECHOPAIR_P(SP_E_LBL, e);
     SERIAL_ECHOPAIR(" (", position.e);
     SERIAL_ECHOPAIR("->", target.e);
     SERIAL_ECHOLNPGM(")");

Marlin/src/module/scara.cpp

       current_position[axis] = cartes[axis];
     #else
       // MP_SCARA uses a Cartesian XY home position
-      // SERIAL_ECHOLNPAIR("homeposition X:", homeposition.x, " Y:", homeposition.y);
+      // SERIAL_ECHOPGM("homeposition");
+      // SERIAL_ECHOLNPAIR_P(SP_X_LBL, homeposition.x, SP_Y_LBL, homeposition.y);
       current_position[axis] = homeposition[axis];
     #endif
 
-    // SERIAL_ECHOLNPAIR("Cartesian X:", current_position.x, " Y:", current_position.y);
+    // SERIAL_ECHOPGM("Cartesian");
+    // SERIAL_ECHOLNPAIR_P(SP_X_LBL, current_position.x, SP_Y_LBL, current_position.y);
     update_software_endstops(axis);
   }
 }

Marlin/src/module/stepper.cpp

   #if CORE_IS_XY || CORE_IS_XZ || ENABLED(DELTA) || IS_SCARA
     SERIAL_ECHOPAIR(STR_COUNT_A, pos.x, " B:", pos.y);
   #else
-    SERIAL_ECHOPAIR(STR_COUNT_X, pos.x, " Y:", pos.y);
+    SERIAL_ECHOPAIR_P(PSTR(STR_COUNT_X), pos.x, SP_Y_LBL, pos.y);
   #endif
   #if CORE_IS_XZ || CORE_IS_YZ || ENABLED(DELTA)
     SERIAL_ECHOLNPAIR(" C:", pos.z);
   #else
-    SERIAL_ECHOLNPAIR(" Z:", pos.z);
+    SERIAL_ECHOLNPAIR_P(SP_Z_LBL, pos.z);
   #endif
 }