tidy-up: miscellaneous

- avoid "will" in builds scripts, scripts folder, curl_easy_ssls_export.md,
  and few other files.
- badwords: add "initialise", "nul terminated", "thread safety" and
  variations.
- prefer "null-terminat", where missing (two places).
- fix "null-terminat*" missing dash.
- hostip: merge two `#if` blocks.
- tool_doswin: fix comment
  Spotted by GitHub Code Quality
  Follow-up to 9a2663322c #17572
- fix stray spaces and newlines.

Closes #21638

tests/ftpserver.pl

@@ -196,9 +196,9 @@ my $TEXT_PASSWORD = "secret";
 my $POP3_TIMESTAMP = "<1972.987654321\@curl>";
 
 #**********************************************************************
-# exit_signal_handler will be triggered to indicate that the program
+# exit_signal_handler is triggered to indicate that the program
 # should finish its execution in a controlled way as soon as possible.
-# For now, program will also terminate from within this handler.
+# For now, program also terminates from within this handler.
 #
 sub exit_signal_handler {
     my $signame = shift;
@@ -227,9 +227,9 @@ sub ftpmsg {
 }
 
 #**********************************************************************
-# eXsysread is a wrapper around perl's sysread() function. This will
-# repeat the call to sysread() until it has actually read the complete
-# number of requested bytes or an unrecoverable condition occurs.
+# eXsysread is a wrapper around perl's sysread() function. This repeats
+# the call to sysread() until it has actually read the complete number
+# of requested bytes or an unrecoverable condition occurs.
 # On success returns a positive value, the number of bytes requested.
 # On failure or timeout returns zero.
 #
@@ -531,7 +531,7 @@ sub senddata {
 #**********************************************************************
 # protocolsetup initializes the 'displaytext' and 'commandfunc' hashes
 # for the given protocol. References to protocol command callbacks are
-# stored in 'commandfunc' hash, and text which will be returned to the
+# stored in 'commandfunc' hash, and text which is returned to the
 # client before the command callback runs is stored in 'displaytext'.
 #
 sub protocolsetup {