`requirements-dev.txt`, but none of the others, was tracked withWindows-style (CRLF) line endings. This appears to have been thecase since it was introduced ina1b7634 (as `dev-requirements.txt`)and not to be intentional.This only changes how it is stored in the repository. This does notchange `.gitattributes` (it is not forced to have LF line endingsif automatic line-ending conversions are configured in Git).

This resolves two warnings about Ruff configuration, by:- No longer setting `ignore-init-module-imports = true` explicitly,  which was deprecated since `ruff` 0.4.4. We primarily use `ruff`  via `pre-commit`, for which this deprecation has applied since we  upgraded the version in `.pre-commit-config.yaml` from 0.4.3 to  0.6.0 ind1582d1 (gitpython-developers#1953).  We continue to list `F401` ("Module imported but unused") as not  automatically fixable, to avoid inadvertently removing imports  that may be needed.  See also:https://docs.astral.sh/ruff/settings/#lint_ignore-init-module-imports- Rename the rule `TCH004` to `TC004`, since `TCH004` is the old  name that may eventually be removed and that is deprecated since  0.8.0. We upgraded `ruff` in `.pre-commit-config.yml` again inb7ce712 (gitpython-developers#2031), from 0.6.0 to 0.11.12, at which point this  deprecation applied.  See alsohttps://astral.sh/blog/ruff-v0.8.0.These changes make those configuration-related warnings go away,and no new diagnostics (errors/warnings) are produced when running`ruff check` or `pre-commit run --all-files`. No F401-relateddiagnostics are triggered when testing with explicit`ignore-init-module-imports = false`, in preview mode or otherwise.In addition, this commit makes two changes that are not needed toresolve warnings:- Stop excluding `E203` ("Whitespace before ':'"). That diagnostic  is no longer failing with the current code here in the current  version of `ruff`, and code changes that would cause it to fail  would likely be accidentally mis-st- Add the version lower bound `>=0.8` for `ruff` in  `requirements-dev.txt`. That file is rarely used, as noted ina8a73ff (gitpython-developers#1871), but as long as we have it, there may be a  benefit to excluding dependency versions for which our  configuration is no longer compatible. This is the only change in  this commit outside of `pyproject.toml`.

This stops listing Ruff rule `E731` ("Do not assign a `lambda`expression, use a `def`") as ignored, and fixes all occurrences ofit:- Spacing is manually adjusted so that readability is not harmed,  while still satisfying the current formatting conventions.- Although the affected test modules do not currently use type  annotations, the non-test modules do. Some of the lambdas already  had type annotations, by annotating the variable itself with an  expression formed by subscripting `Callable`. This change  preserves them, converting them to paramter and return type  annotations in the resulting `def`. Where such type annotations  were absent (in lambdas in non-test modules), or partly absent,  all missing annotations are added to the `def`.- Unused paramters are prefixed with a `_`.- `IndexFile.checkout` assigned a lambda to `make_exc`, whose body  was somewhat difficult to read. Separately from converting it to  a `def`, this refactors the expression in the `return` statement  to use code like `(x, *ys)` in place of `(x,) + tuple(ys)`.This change does not appear to have introduced (nor fixed) any`mypy` errors.This only affects lambdas that were assigned directly to variables.Other lambda expressions remain unchanged.