build: setup ng-dev format pre-commit hook

Whenever a commit is being created, the `yarn ng-dev format changed`
command is being executed. This means that the formatter does not
need to be run manually.

.husky/pre-commit

@@ -0,0 +1,11 @@
+#!/bin/sh
+. "$(dirname "$0")/_/husky.sh"
+
+# Allow for the formatting command to fail without exiting the script.
+set +e
+
+yarn -s ng-dev format staged 2>/dev/null
+
+if [ $? -ne 0 ]; then
+  echo "WARNING: failed to run file formatting (ng-dev format staged)"
+fi

DEV_ENVIRONMENT.md

@@ -64,3 +64,18 @@ packages locally and test them by either of the following ways:
 If you're making changes to a public API, they need to be propagated to our public API golden files.
 To save the changes you can run `yarn approve-api <target>` and to review the changes, you can look
 at the file under `tools/public_api_guard/<target>.d.ts`.
+
+
+### Disabling Git hooks
+
+If your development workflow does not intend the commit message validation to run automatically
+when commits are being created, or if you do not want to run the formatter upon `git commit`, you
+can disable any installed Git hooks by setting `HUSKY=0` in your shell environment. e.g.
+
+```bash
+# .zshrc
+export HUSKY=0
+
+# .bashrc
+export HUSKY=0
+```