bug#24694: Document url--allow-chars for external use?

[Eli Zaretskii]

> Cc: 24694@debbugs.gnu.org
> From: Hong Xu <hong@topbug.net>
> Date: Fri, 11 Oct 2019 19:21:34 -0700
> 
> Thanks, I've updated the patch as attached.

I have a couple of minor comments:

> * url-util.el (url-hexify-string): Accept a list of allowed chars.
> * url.texi (URI Encoding): Update url-hexify-string doc and index
> improvements.

The log message should specify each file with leading directories
starting from the root of the Emacs tree.  E.g., url-util.el should be
shown as lisp/url/url-util.el.

Also, please always mention the bug number in the log message.

These and other stylistic issues are described in detail in
CONTRIBUTE.

> +allowed characters.  Otherwise, ALLOWED-CHARS should be either a
> +vector whose Nth element is non-nil if character N is allowed or
> +a list of allowed chars.                                     ^

Please insert a comma where indicated, it will make the sentence
easier to read.

Thanks.