DOC: move release note for #36155
xref https://github.com/pandas-dev/pandas/pull/36155#issuecomment-687846461

does not need backport. release note already in 1.1.2 on backport branch
shouldn't this just be in 1.2? > shouldn't this just be in 1.2?

see https://github.com/pandas-dev/pandas/pull/36187#issue-481307046

> does not need backport. release note already in 1.1.2 on backport branch

changes should not really have been applied to the backport branch directly

feel free to change milestone if you think more appropriate. ahh i c, yeah in retrospect we shouldn't have merged the docs in 1.2 at all.