tidy-up: miscellaneous

- drop stray duplicate empty lines in docs, scripts, test data, include,
  examples, tests.
- drop duplicate PP parenthesis.
- curl-functions.m4: move literals to the right side in if expressions,
  to match rest of the source code.
- FAQ.md: delete language designator from an URL.
- packages: apply clang-format (OS400, VMS).
- scripts/schemetable.c: apply clang-format.
- data320: delete duplicate empty line that doesn't change the outcome.
- spacecheck: extend to check for duplicate empty lines
  (with exceptions.)
- fix whitespace nits

Closes #19936

tests/unit/unit1397.c

@@ -39,8 +39,8 @@ static CURLcode test_unit1397(const char *arg)
   };
 
   static const struct testcase tests[] = {
-    {".hello.com", "*.hello.com", FALSE },
-    {"a.hello.com", "*.hello.com", TRUE },
+    { ".hello.com", "*.hello.com", FALSE },
+    { "a.hello.com", "*.hello.com", TRUE },
     { "", "", FALSE },
     { "a", "", FALSE },
     { "", "b", FALSE },