badwords: re-sync with curl-www, fix issues found

Also:
- replace `manpage` with `man page`, add to `badwords.txt`.
- badwords.pl: import `-w` feature from curl-www, syncing the two
  scripts fully.
- badwords.txt: import missing items from curl-www, syncing the two
  files fully.
- pyspelling.words: drop `cURL` allowed word.

Closes #19468

tests/data/test1140

@@ -11,7 +11,7 @@ documentation
 # Client-side
 <client>
 <name>
-Verify the nroff of manpages
+Verify the nroff of man pages
 </name>
 
 <command type="perl">

tests/data/test1488

@@ -11,7 +11,7 @@ manpages
 # Client-side
 <client>
 <name>
-symbols-in-versions and manpages agree on added-in versions
+symbols-in-versions and man pages agree on added-in versions
 </name>
 
 <command type="perl">

tests/data/test1705

@@ -12,7 +12,7 @@ managen
 <client>
 
 <name>
-managen makes manpage
+managen makes man page
 </name>
 
 <file name="%LOGDIR/mainpage.idx">
@@ -191,7 +191,7 @@ option2.md:15:1:WARN: see-also a non-existing option: proto-default
 .\" *
 .\" **************************************************************************
 .\"
-.\" DO NOT EDIT. Generated by the curl project managen manpage generator.
+.\" DO NOT EDIT. Generated by the curl project managen man page generator.
 .\"
 .TH curl 1 "%DATE" "curl %VERNUM" "curl Manual"
 .SH DESCRIPTION