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

src/tool_setup.h

@@ -33,7 +33,7 @@
  * _LARGE_FILES in order to support files larger than 2 GB. On platforms
  * where this happens it is mandatory that these macros are defined before
  * any system header file is included, otherwise file handling function
- * prototypes will be misdeclared and curl tool may not build properly;
+ * prototypes are misdeclared and curl tool may not build properly;
  * therefore we must include curl_setup.h before curl.h when building curl.
  */