Extend SERIAL_CHAR to take multiple arguments

Marlin/src/feature/bedlevel/bedlevel.cpp

@@ -207,8 +207,7 @@ void reset_bed_level() {
         #endif
       }
       #ifdef SCAD_MESH_OUTPUT
-        SERIAL_CHAR(' ');
-        SERIAL_CHAR(']');                     // close sub-array
+        SERIAL_CHAR(' ', ']');                    // close sub-array
         if (y < sy - 1) SERIAL_CHAR(',');
       #endif
       SERIAL_EOL();

Marlin/src/feature/runout.h

@@ -213,7 +213,7 @@ class FilamentSensorBase {
           if (change) {
             SERIAL_ECHOPGM("Motion detected:");
             for (uint8_t e = 0; e < NUM_RUNOUT_SENSORS; e++)
-              if (TEST(change, e)) { SERIAL_CHAR(' '); SERIAL_CHAR('0' + e); }
+              if (TEST(change, e)) SERIAL_CHAR(' ', '0' + e);
             SERIAL_EOL();
           }
         #endif