Git pre-push hook should be generated to location defined by core.hooksPath #2853

In our project, we define all our git hooks at .githooks, so we can version control them and have them shared amongst our team. We recommend that those in our project set up the git hooks by running git config --local unset core.hooksPath.

The git pre-push hook generated by ./gradlew spotlessInstallGitPrePushHook writes the hook to .git/hooks, instead of wherever git config core.hooksPath is pointing to. By default, git config core.hooksPath is equivalent to .git/hooks, but it can be customised to something else, like in our case.