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

scripts/cd2nroff

@@ -25,7 +25,7 @@
 
 =begin comment
 
-Converts a curldown file to nroff (manpage).
+Converts a curldown file to nroff (man page).
 
 =end comment
 =cut
@@ -431,7 +431,7 @@ sub single {
         # convert backslash-'<' or '> to just the second character
         $d =~ s/\\([<>])/$1/g;
 
-        # mentions of curl symbols with manpages use italics by default
+        # mentions of curl symbols with man pages use italics by default
         $d =~ s/((lib|)curl([^ ]*\(3\)))/\\fI$1\\fP/gi;
 
         # backticked becomes italics

scripts/managen

@@ -25,7 +25,7 @@
 
 =begin comment
 
-This script generates the manpage.
+This script generates the man page.
 
 Example: managen <command> [files] > curl.1
 
@@ -64,7 +64,7 @@ my $globals;
 my $error = 0;
 my $indent = 4;
 
-# get the long name version, return the manpage string
+# get the long name version, return the man page string
 sub manpageify {
     my ($k, $manpage)=@_;
     my $trail = '';
@@ -412,7 +412,7 @@ sub render {
                 print STDERR "$f:$line:1:WARN: un-escaped < or > used: $nontick\n";
             }
 
-            # if there is a space, it needs quotes for manpage
+            # if there is a space, it needs quotes for man page
             if(($word =~ / /) && $manpage) {
                 $word = "\"$word\"";
             }
@@ -1253,7 +1253,7 @@ sub mainpage {
 .\\" *
 .\\" **************************************************************************
 .\\"
-.\\" 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 $version" "curl Manual"
 HEADER