badwords: rework exceptions, fix many of them

Also:
- support per-directory and per-upper-directory whitelist entries.
- convert badlist input grep tweak into the above format.
  (except for 'And' which had just a few hits.)
- fix many code exceptions, but do not enforce.
  (there also remain about 350 'will' uses in lib)
- fix badwords in example code, drop exceptions.
- badwords-all: convert to Perl.
  To make it usable from CMake.
- FAQ: reword to not use 'will'. Drop exception.

Closes #20886

lib/pop3.c

@@ -1230,7 +1230,7 @@ static CURLcode pop3_state_command_resp(struct Curl_easy *data,
      when there is no body to return. */
   pop3c->eob = 2;
 
-  /* But since this initial CR LF pair is not part of the actual body, we set
+  /* Since this initial CR LF pair is not part of the actual body, we set
      the strip counter here so that these bytes will not be delivered. */
   pop3c->strip = 2;