message: clarify that git hooks may be overwritten
diff: @@ -17,7 +17,9 @@ Ginkgo adds the following additional switches to control what is being built:
  * `-DGINKGO_DEVEL_TOOLS={ON, OFF}` sets up the build system for development
  (requires clang-format, will also download git-cmake-format),
  - default is `OFF`.
  + default is `OFF`. If it is set to `ON`, a pre-commit hook for formatting
  + will be installed. This hook may overwrite a user defined pre-commit hook
  + when Ginkgo is used as a submodule.
  * `-DGINKGO_MIXED_PRECISION={ON, OFF}` compiles true mixed-precision kernels
  instead of converting data on the fly, default is `OFF`.
  Enabling this flag increases the library size, but improves performance of
  