Paying more attention to PRs

Nobody has claimed this yet.

# Motivation

Some practical examples:
* @gi0e5b06 forked LMMS, one critique was he expects PRs to be answered immediatelly (and I agree here, I'd say ideally, no "PR" should ever be open and waiting for review)
* One of my PRs (instr-sub-plugins) didn't get attention for two months, many others are still not reviewed.

# Why PRs need more attention

* Coders forget what they did and has more difficulties to answer a review if it's months ago
* Coder says: "I've waited long enough, no comments, so I'll merge". Can make sense, but every bug you merge into master will
affect others (look at our unstable master branch)

# What are the reasons for PRs not reviewed?

At least:
* I often don't know when a PR is ready for review. Should this be marked in the title? Like "[ready] Some title".
* Style review sucks, it should be done by CI. We could use the clang stuff (#4690, #6323) or/and some shell scripts.
* Maybe this is also a current problem of people focussing on 1.2 issues, ignoring master PRs.

Start by reviewing the proposed causes and the referenced issues #4690 and #6323, including the suggested clang checks and shell scripts. The issue does not define a specific implementation, files, tests, or measurable completion criteria, so the desired workflow would need to be decided before work can begin.

Written by the indexing model from the issue text.