Fix pre-commit hook; add CMake formatting pre-commit

[jwallwork23]

Fix pre-commit hook; add CMake formatting pre-commit

There was a minor issue in the pre-commit hook because the final lines checked for differences in nextsim_precommit_before.patch and nextsim_precommit_after.patch but these were replaced with calls to mktemp.

While fixing this, I realised we aren't currently formatting CMakeLists.txt files but tools for this exist. Let me know if this is something we'd like to include.

I also added some docs on how to get the pre-commit hook set up.

(Almost all of the changes in this PR are auto-formatting.)

[timspainNERSC]

I like the idea of autoformatting the CMakeLists.txt. But I don't like the formatting changes included in this PR. I like the lists of sources (&c.) with one item per line. I think it's easier to read and also easier to add or remove items, as this corresponds to adding or removing lines, rather than editing lines.

[jwallwork23]

I like the idea of autoformatting the CMakeLists.txt. But I don't like the formatting changes included in this PR. I like the lists of sources (&c.) with one item per line. I think it's easier to read and also easier to add or remove items, as this corresponds to adding or removing lines, rather than editing lines.

Let me see if I can set configure options for that.

[jwallwork23]

Okay, I figured out how to set a config file with these four edits. With these edits, the lint check passes without modification of the code!

[jwallwork23]

This file was generated with

cmake-lint --disabled {C0103,C0113} --tab-size 4 --line-width 100 --dump-config python > .cmake-lint-config.py

so it consists of the defaults plus the four edits. I figure it'd be useful to use the current defaults, given our experience with the default settings of clang-format changing.

[timspainNERSC]

👍