docs: replace exercise for metrics getting-started #5774

	name: HtmlTest

	on:
	push:
	branches:
	- 'main'
	- '[0-9]+.[1-9][0-9]*.x'
	paths:
	- 'docs/**'
	pull_request:
	branches:
	- 'main'
	- '[0-9]+.[1-9][0-9]*.x'
	paths:
	- 'docs/**'

	# Declare default permissions as read only.
	permissions: read-all

	jobs:
	htmltest:
	# The type of runner that the job will run on
	runs-on: ubuntu-latest

	# Steps represent a sequence of tasks that will be executed as part of the job
	steps:
	# Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
	- uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
	with:
	submodules: true
	fetch-depth: 0

	- name: Cache HTMLTest packages
	uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9 # v4
	with:
	path: \|
	tmp/.htmltest
	key: htmltest-${{ hashFiles('tmp/.htmltest/refcache.json') }}

	- name: Check HTML
	run: make htmltest

Provide feedback