tidy-up: mostly whitespace nits

- delete completed TODO from `./CMakeLists.txt`.
- convert a C++ comment to C89 in `./CMake/CurlTests.c`.
- delete duplicate EOLs from EOF.
- add missing EOL at EOF.
- delete whitespace at EOL (except from expected test results).
- convert tabs to spaces.
- convert CRLF EOLs to LF in GHA yaml.
- text casing fixes in `./CMakeLists.txt`.
- fix a codespell typo in `packages/OS400/initscript.sh`.

Closes #11772

tests/data/test549

@@ -42,7 +42,7 @@ FTP RETR over proxy with CURLOPT_PROXY_TRANSFER_MODE
  </name>
 # first URL then proxy
  <command>
-ftp://www.example.com/moo/%TESTNUMBER http://%HOSTIP:%HTTPPORT 
+ftp://www.example.com/moo/%TESTNUMBER http://%HOSTIP:%HTTPPORT
 </command>
 </client>