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

docs/examples/CMakeLists.txt

@@ -47,7 +47,7 @@ foreach(_target IN LISTS COMPLICATED_MAY_BUILD check_PROGRAMS _all)  # keep 'COM
         # CMake generates a static library for the OBJECT target. Silence these 'lib.exe' warnings:
         # warning LNK4006: main already defined in ....obj; second definition ignored
         # warning LNK4221: This object file does not define any previously undefined public symbols,
-        #                  so it will not be used by any link operation that consumes this library
+        #                  [...] not be used by any link operation that consumes this library
         if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.13)
           set_target_properties(${_target_name} PROPERTIES STATIC_LIBRARY_OPTIONS "-ignore:4006;-ignore:4221")
         else()