worktree move: accept destination as directory

Similar to "mv a b/", which is actually "mv a b/a", we extract basename
of source worktree and create a directory of the same name at
destination if dst path is a directory.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

strbuf.h

@@ -179,6 +179,9 @@ extern void strbuf_trim(struct strbuf *);
 extern void strbuf_rtrim(struct strbuf *);
 extern void strbuf_ltrim(struct strbuf *);
 
+/* Strip trailing directory separators */
+extern void strbuf_trim_trailing_dir_sep(struct strbuf *);
+
 /**
  * Replace the contents of the strbuf with a reencoded form.  Returns -1
  * on error, 0 on success.