Revert "Fixed typo"

This reverts commit 400db78cf8e953d411c714fbc224b21b864a07f2.
Revert "[ Release notes ] Added documentation for quoting levels"

This reverts commit ef226aa5374142c8e148245c76bd10d602b20f3b.

Quoting level isn't a new feature (see https://github.com/agda/agda/pull/17#issuecomment-58777304).
[ release notes ] Documented Agda issue 1207