Clang Tidy: Ignore some newer readability warnings

These patterns are very common throughout the Blender codebase, which makes
the clang-tidy output and using clangd in an IDE quite noisy. They were introduced
in LLVM version 18 and 19.

* readability-math-missing-parentheses
* readability-avoid-nested-conditional-operator
* readability-enum-initial-value
* readability-avoid-unconditional-preprocessor-if

Pull Request: https://projects.blender.org/blender/blender/pulls/132462

.clang-tidy

@@ -19,6 +19,10 @@ Checks:  >
   -readability-misleading-indentation,
   -readability-use-anyofallof,
   -readability-identifier-length,
+  -readability-enum-initial-value,
+  -readability-math-missing-parentheses,
+  -readability-avoid-nested-conditional-operator,
+  -readability-avoid-unconditional-preprocessor-if,
 
   -readability-function-cognitive-complexity,