badwords: fix issues found in tests

There remain some false positives, hits in test data, and `dir` use,
around 100 issues in total.

There is no plan to enforce badwords on tests.

Also:
- badwords.txt: let a few `manpage[s]` occurrences through
  (in Perl code).

Closes #19541

tests/devtest.pl

@@ -24,13 +24,13 @@
 ###########################################################################
 
 # This script is intended for developers to test some internals of the
-# runtests.pl harness. Don't try to use this unless you know what you're
+# runtests.pl harness. Do not try to use this unless you know what you are
 # doing!
 
 # An example command-line that starts a test http server for test 11 and waits
 # for the user before stopping it:
 #   ./devtest.pl --verbose serverfortest https echo "Started https" protoport https preprocess 11 pause echo Stopping stopservers echo Done
-# curl can connect to the server while it's running like this:
+# curl can connect to the server while it is running like this:
 #   curl -vkL https://localhost:<protoport>/11
 
 use strict;
@@ -94,7 +94,7 @@ sub parseprotocols {
 
     # Generate a "proto-ipv6" version of each protocol to match the
     # IPv6 <server> name and a "proto-unix" to match the variant which
-    # uses Unix domain sockets. This works even if support isn't
+    # uses Unix domain sockets. This works even if support is not
     # compiled in because the <features> test will fail.
     push @protocols, map(("$_-ipv6", "$_-unix"), @protocols);