tidy-up: miscellaneous

- examples: sync debug output printf masks.
- INSTALL-CMAKE.md: tidy up section for some options.
- curl_sha512_256: delete comment suggesting an optimization.
- vtls/keylog: scope a variable.
- vtls/openssl: make a source code URL a permalink.
- vtls/schannel: drop redundant parentheses.
- test1119.pl: robustify `$1` -> `$s`.
- sync arg names in comments to match the code.
- tidy up and minor fixes to comments.
- fix formatting/indenting/comment/newline/include nits.
- move `UNITTEST` protos next to definitions, sync their argument names.
- make variables static.
- add parentheses to Perl `open()` calls.
- drop unnecessary double quotes in Perl.
- clang-format.

Closes #21000

tests/tunit/tool1394.c

@@ -22,7 +22,6 @@
  *
  ***************************************************************************/
 #include "unitcheck.h"
-
 #include "tool_getparam.h"
 
 static CURLcode test_tool1394(const char *arg)

tests/tunit/tool1604.c

@@ -24,7 +24,6 @@
 #include "unitcheck.h"
 
 #if defined(_WIN32) || defined(MSDOS)
-
 #include "tool_cfgable.h"
 #include "tool_doswin.h"
 

tests/tunit/tool1621.c

@@ -22,7 +22,6 @@
  *
  ***************************************************************************/
 #include "unitcheck.h"
-
 #include "tool_xattr.h"
 
 static CURLcode test_tool1621(const char *arg)

tests/tunit/tool1622.c

@@ -22,7 +22,6 @@
  *
  ***************************************************************************/
 #include "unitcheck.h"
-
 #include "tool_progress.h"
 
 static CURLcode test_tool1622(const char *arg)

tests/tunit/tool1623.c

@@ -22,7 +22,6 @@
  *
  ***************************************************************************/
 #include "unitcheck.h"
-
 #include "tool_getparam.h"
 
 struct check1623 {