builtin: fix typos

Fix typos in comments.

Signed-off-by: Andrew Kreimer <algonell@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/help.c

@@ -542,7 +542,7 @@ static void open_html(const char *path)
 
 static void show_html_page(const char *page)
 {
-	struct strbuf page_path; /* it leaks but we exec bellow */
+	struct strbuf page_path; /* it leaks but we exec below */
 
 	get_html_page_path(&page_path, page);
 

builtin/ls-files.c

@@ -507,7 +507,7 @@ static int get_common_prefix_len(const char *common_prefix)
 	common_prefix_len = strlen(common_prefix);
 
 	/*
-	 * If the prefix has a trailing slash, strip it so that submodules wont
+	 * If the prefix has a trailing slash, strip it so that submodules won't
 	 * be pruned from the index.
 	 */
 	if (common_prefix[common_prefix_len - 1] == '/')

builtin/name-rev.c

@@ -65,7 +65,7 @@ static void set_commit_cutoff(struct commit *commit)
 static void adjust_cutoff_timestamp_for_slop(void)
 {
 	if (cutoff) {
-		/* check for undeflow */
+		/* check for underflow */
 		if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
 			cutoff = cutoff - CUTOFF_DATE_SLOP;
 		else

builtin/receive-pack.c

@@ -1325,7 +1325,7 @@ static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 }
 
 /*
- * NEEDSWORK: we should consolidate various implementions of "are we
+ * NEEDSWORK: we should consolidate various implementations of "are we
  * on an unborn branch?" test into one, and make the unified one more
  * robust. !get_sha1() based check used here and elsewhere would not
  * allow us to tell an unborn branch from corrupt ref, for example.