Harmonize pretty print settings

[pokrakam]

In the same principle as #773, different code uses different styles for keyword/identifier upper/lower case.

Propose standardising on the most commonly used format of keyword upper / identifier lower case to minimise large diffs due to pretty print.

See also Style Guides on the topic.

[larshp]

also see #658

[pokrakam]

Didn't spot that one. I did search for an issue about this, but only open ones.

[AndreaBorgia-Abo]

So, if I understand it correctly, this should be once-in-project-lifetime occurrence: once the "keywords in uppercase / identifiers in lowercase" consensus reached in #658 is implemented, we shouldn't have to deal with this issue any more.
In this case, I'll move this one to my todolist and review it quickly.

[pokrakam]

Correct, and with abapLint we can verify that all PRs conform in future.

[AndreaBorgia-Abo]

Guess I'll now have to learn how to deploy the linter in my setup, now :)