Custom class: Change map API #2983
Description
Motivation
#2947 added a new apply API which is necessary for plugin compatibility. This API had to include a language parameter because it was required by the map API.
However, this language parameter doesn't really make sense. Mapping aliases should be language-independent especially considering embedded languages.
The language parameter is also a problem for plugin compatibility. Some plugins (e.g. File highlight, JSONP highlight) change the code and language of a code block. It's not possible for other plugins to determine the language before those plugins.
Description
Remove the language parameter from both the map and apply API.