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/vim9compile.c b/src/vim9compile.c
index e95340c..bdaf1ed 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1041,7 +1041,7 @@
 	// Skip the opening {.
 	block_start = skipwhite(p + 1);
 	block_end = block_start;
-	if (*block_start != NUL &&skip_expr(&block_end, NULL) == FAIL)
+	if (*block_start != NUL && skip_expr(&block_end, NULL) == FAIL)
 	    return FAIL;
 	block_end = skipwhite(block_end);
 	// The block must be closed by a }.