Improve optimize component doc.

Signed-off-by: crynobone <crynobone@gmail.com>
Add parser component to toc.

Signed-off-by: crynobone <crynobone@gmail.com>
Add usage title.

Signed-off-by: crynobone <crynobone@gmail.com>
Merge branch '2.1' into 2.2

Signed-off-by: crynobone <crynobone@gmail.com>

Conflicts:
	src/components/debug/index.md
	src/components/foundation/index.md