DOC: fix the incorrect doc style in 1.2.1
@jorisvandenbossche pls following up and fix the docs


it's not a style issue rather this is completely inconsistent with the current docs 

we NEVER use the style - always ipython docs style

__Originally posted by @jreback in https://github.com/pandas-dev/pandas/pull/39239#issuecomment-763475054__