mathlib

8a89b063 - refactor(analysis/calculus/mean_value): prove the mean value theorem using 1D derivative (#1740)

refactor(analysis/calculus/mean_value): prove the mean value theorem using 1D derivative (#1740) * refactor(analysis/calculus/mean_value): prove the mean value theorem using 1D derivative * docstring * use iff.rfl * fix build * fix docstring