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/devtest.pl

@@ -64,7 +64,6 @@ use testutil qw(
     );
 use getpart;
 
-
 #######################################################################
 # logmsg is our general message logging subroutine.
 # This function is currently required to be here by servers.pm
@@ -105,7 +104,6 @@ sub parseprotocols {
     push @protocols, 'none';
 }
 
-
 #######################################################################
 # Initialize @protocols from the curl binary under test
 #
@@ -117,7 +115,6 @@ sub init_protocols {
     }
 }
 
-
 #######################################################################
 # Initialize the test harness to run tests
 #