Fix monkeypatch doc
Fix monkeypatch doc

`delenv` is incorrectly documented.
davidszotten/pytest,Akasurde/pytest,alfredodeza/pytest,markshao/pytest,tomviner/pytest,RonnyPfannschmidt/pytest,hackebrot/pytest,tomviner/pytest,ddboline/pytest,nicoddemus/pytest,nicoddemus/pytest,txomon/pytest,pfctdayelise/pytest,pytest-dev/pytest,The-Compiler/pytest,The-Compiler/pytest