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

scripts/badwords-all

@@ -1,12 +1,14 @@
-#!/bin/sh
+#!/usr/bin/env perl
 # Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # SPDX-License-Identifier: curl
 
-set -eu
+use strict;
+use warnings;
 
-cd "$(dirname "${0}")"/..
+use File::Basename;
 
-# we allow some extra in source code
-grep -Ev '^(will:|But=|So=|And=| url=)' scripts/badwords.txt | scripts/badwords -a src lib include docs/examples
-scripts/badwords -w scripts/badwords.ok '**.md' projects/OS400/README.OS400 < scripts/badwords.txt
+chdir dirname(__FILE__) . "/..";
+
+system("scripts/badwords -a -w scripts/badwords.ok src lib include docs/examples < scripts/badwords.txt");
+system("scripts/badwords    -w scripts/badwords.ok '**.md' projects/OS400/README.OS400 < scripts/badwords.txt");