Remove `clang-format`ing of generated sources.

[1uc]

NMODL should generate code that's sensible formatted.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9df433b) 88.38% compared to head (965fe2e) 88.38%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1160 +/- ## ======================================= Coverage 88.38% 88.38% ======================================= Files 176 176 Lines 12946 12946 ======================================= Hits 11442 11442 Misses 1504 1504 ```

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[ohm314]

So, here's the thing with this PR. I remember specifically there has been already plenty of back-and-forth about the question of formatting generated code. I feel like about once every year someone decides that it needs to be done differently. I thought with Tristan we had said that "no, we will not care too much about directly generating correctly formatted code, it should be of course readable, but we leave consistent formatting up to a tool that knows well how to do this, hence clang-format. So now I wonder, why should we change this policy? I'm not fundamentally against, but I want to avoid us to do changes that are unnecessary.

oh and if I missed an offline discussion around this (or worse, forgot about it) please ignore this.