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

acinclude.m4

@@ -769,7 +769,7 @@ AC_DEFUN([CURL_CHECK_STRUCT_TIMEVAL], [
         #include <time.h>
       ]],[[
         struct timeval ts;
-        ts.tv_sec  = 0;
+        ts.tv_sec = 0;
         ts.tv_usec = 0;
         (void)ts;
       ]])