refactor: update prettier and doctoc (#5605)

* docs: add toc to CODE OF CONDUCT

* chore: add prettier ignore blocks to docs

* chore: update styles for Dockerfile

* refactor: separate prettier, doctoc

This does a couple things:
- update `.prettierignore`
- split `prettier` and `doctoc` commands. you can still run with `yarn
  fmt`
- delete `fmt.sh` and add `doctoc.sh`

By doing so, we can run tasks in parallel in CI and we should also have
less false positives than before with `yarn fmt` locally.

* refactor: update prettier job, add doctoc

This modifies the prettier job to use actionsx/prettier. It also adds a
job for `doctoc`.

* chore: upgrade to prettier 2.7.1

* chore: pin doctoc to 2.0.0

* fixup!: add .pc to prettierignore

* feat: add --cache to prettier cmd

ci/dev/doctoc.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+main() {
+  cd "$(dirname "$0")/../.."
+
+  doctoc --title '# FAQ' docs/FAQ.md > /dev/null
+  doctoc --title '# Setup Guide' docs/guide.md > /dev/null
+  doctoc --title '# Install' docs/install.md > /dev/null
+  doctoc --title '# npm Install Requirements' docs/npm.md > /dev/null
+  doctoc --title '# Contributing' docs/CONTRIBUTING.md > /dev/null
+  doctoc --title '# Maintaining' docs/MAINTAINING.md > /dev/null
+  doctoc --title '# Contributor Covenant Code of Conduct' docs/CODE_OF_CONDUCT.md > /dev/null
+  doctoc --title '# iPad' docs/ipad.md > /dev/null
+  doctoc --title '# Termux' docs/termux.md > /dev/null
+
+  if [[ ${CI-} && $(git ls-files --other --modified --exclude-standard) ]]; then
+    echo "Files need generation or are formatted incorrectly:"
+    git -c color.ui=always status | grep --color=no '\[31m'
+    echo "Please run the following locally:"
+    echo "  yarn doctoc"
+    exit 1
+  fi
+}
+
+main "$@"