Multi-line comments cleanup (#19535)

Marlin/src/gcode/feature/L6470/M906.cpp

@@ -33,7 +33,6 @@
 #include "../../../core/debug_out.h"
 
 /**
- *
  * M906: report or set KVAL_HOLD which sets the maximum effective voltage provided by the
  *       PWMs to the steppers
  *
@@ -56,7 +55,6 @@
  *
  * L6470 is used in the STEP-CLOCK mode.  KVAL_HOLD is the only KVAL_xxx
  * that affects the effective voltage seen by the stepper.
- *
  */
 
 /**

Marlin/src/gcode/feature/L6470/M916-918.cpp

@@ -37,7 +37,6 @@
 #include "../../../core/debug_out.h"
 
 /**
- *
  * M916: increase KVAL_HOLD until get thermal warning
  *       NOTE - on L6474 it is TVAL that is used
  *
@@ -62,7 +61,6 @@
  *
  * D - time (in seconds) to run each setting of KVAL_HOLD/TVAL
  *     optional - defaults to zero (runs each setting once)
- *
  */
 
 /**
@@ -187,7 +185,6 @@ void GcodeSuite::M916() {
 }
 
 /**
- *
  * M917: Find minimum current thresholds
  *
  *   Decrease OCD current until overcurrent error
@@ -214,7 +211,6 @@ void GcodeSuite::M916() {
  *
  * K - value for KVAL_HOLD (0 - 255) (ignored for L6474)
  *     optional - will report current value from driver if not specified
- *
  */
 void GcodeSuite::M917() {
 
@@ -522,7 +518,6 @@ void GcodeSuite::M917() {
 }
 
 /**
- *
  * M918: increase speed until error or max feedrate achieved (as shown in configuration.h))
  *
  * J - select which driver(s) to monitor on multi-driver axis
@@ -543,7 +538,6 @@ void GcodeSuite::M917() {
  *
  * M - value for microsteps (1 - 128) (optional)
  *     optional - will report current value from driver if not specified
- *
  */
 void GcodeSuite::M918() {