Reported by the new script 'scripts/copyright.pl'. The script has a
regex whitelist for the files that don't need copyright headers.
Removed three (mostly usesless) README files from docs/
Closes#5141
- replace tabs with spaces where possible
- remove line ending spaces
- remove double/triple newlines at EOF
- fix a non-UTF-8 character
- cleanup a few indentations/line continuations
in manual examples
Closes https://github.com/curl/curl/pull/3037
