Convert file-level rustfmt skip to fn level skips

[joostjager]

Extend the approach proposed in #3767 to the full repository. The change set is automatically generated using a script. The script omits skip directives when they would not impact formatting (code already rustfmt-compliant).

I've fixed various problems with the script, and it may be that there are a few edge cases left that should have had a skip directive. There could also be a few redundant ones. I think we can live with that.

[ldk-reviews-bot]

👋 Hi! I see this is a draft PR.
I'll wait to assign reviewers until you mark it as ready for review.
Just convert it out of draft status when you're ready for review!

[joostjager]

As discussed in sync meet, I will try to extend the script to ignore rustfmt changes that only affect the function signature.

[joostjager]

Pushed fix up commit to ignore sig changes. Modest reduction in skips, with a few edge cases.

[codecov]

Codecov Report

Attention: Patch coverage is 92.14929% with 61 lines in your changes missing coverage. Please review.

Project coverage is 89.79%. Comparing base (8aae34e) to head (cf4e480).

Files with missing lines	Patch %	Lines
lightning/src/ln/peer_handler.rs	67.53%	25 Missing ⚠️
lightning/src/routing/utxo.rs	31.25%	11 Missing ⚠️
lightning/src/routing/scoring.rs	69.69%	10 Missing ⚠️
lightning/src/routing/router.rs	71.42%	8 Missing ⚠️
lightning/src/chain/channelmonitor.rs	91.89%	6 Missing ⚠️
lightning/src/lib.rs	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3809      +/-   ##
==========================================
+ Coverage   89.73%   89.79%   +0.05%     
==========================================
  Files         159      159              
  Lines      128910   129545     +635     
  Branches   128910   129545     +635     
==========================================
+ Hits       115676   116323     +647     
+ Misses      10536    10533       -3     
+ Partials     2698     2689       -9     

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[tnull]

Why is this in draft? This needs a rebase by now, too.

[tnull]

This was put here deliberately as we opted against running rustfmt on autogenerated files. We need to fix it either way, likely just revert it to include the skip.