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/tftp.c

@@ -175,7 +175,7 @@ static CURLcode tftp_set_timeouts(struct tftp_conn *state)
   /* Average reposting an ACK after 5 seconds */
   state->retry_max = (int)timeout / 5;
 
-  /* But bound the total number */
+  /* Bound the total number */
   if(state->retry_max < 3)
     state->retry_max = 3;
 
@@ -370,9 +370,9 @@ static CURLcode tftp_tx(struct tftp_conn *state, tftp_event_t event)
       int rblock = getrpacketblock(&state->rpacket);
 
       if(rblock != state->block &&
-         /* There is a bug in tftpd-hpa that causes it to send us an ack for
-          * 65535 when the block number wraps to 0. So when we are expecting
-          * 0, also accept 65535. See
+         /* There is a bug in tftpd-hpa that causes it to send us an ACK for
+          * 65535 when the block number wraps to 0. To handle it, when we are
+          * expecting 0, also accept 65535. See
           * https://www.syslinux.org/archives/2010-September/015612.html
           * */
          !(state->block == 0 && rblock == 65535)) {
@@ -418,7 +418,7 @@ static CURLcode tftp_tx(struct tftp_conn *state, tftp_event_t event)
       return CURLE_OK;
     }
 
-    /* TFTP considers data block size < 512 bytes as an end of session. So
+    /* TFTP considers data block size < 512 bytes as an end of session, so
      * in some cases we must wait for additional data to build full (512 bytes)
      * data block.
      * */