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/debugger.c b/src/debugger.c
index 87cd398..38d1fb6 100644
--- a/src/debugger.c
+++ b/src/debugger.c
@@ -22,7 +22,7 @@
 
 static char_u *debug_oldval = NULL;	// old and newval for debug expressions
 static char_u *debug_newval = NULL;
-static int     debug_expr   = 0;        // use debug_expr
+static int     debug_expr   = 0;	// use debug_expr
 
     int
 has_watchexpr(void)