Now printing "now a keyword" only in verbose mode.
Revert "Essai où assert_style n'est utilisé que si pas visuellement une équation;" which was committed by mistake.

This reverts commit a53b44aa042cfded28c34205074f194de7e2e4ee.
Revert "Fixing a loop in proof reconstruction for congruence (#2447)."
committed by mistake. The message pretended to have a fix which is only
superficially a fix. The problem is more complex.

This reverts commit 251218905daea0838a3738466afa1c278bb3e81b.