patch 8.2.4928: various white space and cosmetic mistakes

Problem:    Various white space and cosmetic mistakes.
Solution:   Change spaces to tabs, improve comments.
diff --git a/src/keymap.h b/src/keymap.h
index e8832d6..6350772 100644
--- a/src/keymap.h
+++ b/src/keymap.h
@@ -276,7 +276,7 @@
     , KE_CANCEL = 102		// return from vgetc()
     , KE_COMMAND = 103		// <Cmd> special key
     , KE_SCRIPT_COMMAND = 104	// <ScriptCmd> special key
-    , KE_S_BS = 105	        // shift + <BS>
+    , KE_S_BS = 105		// shift + <BS>
 };
 
 /*