Tweaks to pins comments

Marlin/pins_CHEAPTRONIC.h

 #define BLEN_B 1
 #define BLEN_A 0
 
-// Cheaptronic v1.0 does not use this port
+// Cheaptronic v1.0 doesn't use this
 #define SDCARDDETECT_PIN -1

Marlin/pins_MEGATRONICS_2.h

 #define BLEN_B 1
 #define BLEN_A 0
 
-#define SDCARDDETECT_PIN -1  // Megatronics does not use this port
+#define SDCARDDETECT_PIN -1  // Megatronics doesn't use this

Marlin/pins_MEGATRONICS_3.h

 #define BLEN_B 1
 #define BLEN_A 0
 
-#define SDCARDDETECT_PIN -1	// Megatronics does not use this port
+#define SDCARDDETECT_PIN -1	// Megatronics doesn't use this

Marlin/pins_MINITRONICS.h

 #define BLEN_B 1
 #define BLEN_A 0
 
-#define SDCARDDETECT_PIN -1  // Minitronics does not use this port
+#define SDCARDDETECT_PIN -1  // Minitronics doesn't use this

Marlin/pins_RAMBO.h

     #define BLEN_B 1
     #define BLEN_A 0
 
-    #define SDCARDDETECT_PIN 81 // Ramps doesn't use this port
+    #define SDCARDDETECT_PIN 81 // Ramps doesn't use this
 
   #else //!NEWPANEL - old style panel with shift register
 

Marlin/pins_RAMPS_13.h

       #if ENABLED(G3D_PANEL)
         #define SDCARDDETECT_PIN 49
       #else
-        #define SDCARDDETECT_PIN -1  // Ramps does not use this port
+        #define SDCARDDETECT_PIN -1  // Ramps doesn't use this
       #endif
 
     #endif