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

CMake/CurlTests.c

@@ -283,7 +283,7 @@ static void check(char c)
 int main(void)
 {
   char buffer[1024];
-  /* This will not compile if strerror_r does not return a char* */
+  /* This does not compile if strerror_r does not return a char* */
   /* !checksrc! disable ERRNOVAR 1 */
   check(strerror_r(EACCES, buffer, sizeof(buffer))[0]);
   return 0;
@@ -303,7 +303,7 @@ static void check(float f)
 int main(void)
 {
   char buffer[1024];
-  /* This will not compile if strerror_r does not return an int */
+  /* This does not compile if strerror_r does not return an int */
   /* !checksrc! disable ERRNOVAR 1 */
   check(strerror_r(EACCES, buffer, sizeof(buffer)));
   return 0;