replace has_extension with ends_with

These two are almost the same function, with the exception
that has_extension only matches if there is content before
the suffix. So ends_with(".exe", ".exe") is true, but
has_extension would not be.

This distinction does not matter to any of the callers,
though, and we can just replace uses of has_extension with
ends_with. We prefer the "ends_with" name because it is more
generic, and there is nothing about the function that
requires it to be used for file extensions.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

help.c

@@ -156,7 +156,7 @@ static void list_commands_in_dir(struct cmdnames *cmds,
 			continue;
 
 		entlen = strlen(de->d_name) - prefix_len;
-		if (has_extension(de->d_name, ".exe"))
+		if (ends_with(de->d_name, ".exe"))
 			entlen -= 4;
 
 		add_cmdname(cmds, de->d_name + prefix_len, entlen);