Language: Remove deprecated initEncoding(), recodeForEdit() & recodeInput()

Language: Remove deprecated initEncoding(), recodeForEdit() & recodeInput()

Language::initEncoding(), ::recodeForEdit(), and ::recodeInput() deprecated in
1.28 are now removed.

Usage
=====

* initEncoding() -
  https://codesearch.wmflabs.org/search/?q=initEncoding&i=nope&files=&repos=

* recodeForEdit() -
  https://codesearch.wmflabs.org/search/?q=recodeForEdit&i=nope&files=&repos=

* recodeInput() -
  https://codesearch.wmflabs.org/search/?q=recodeInput&i=nope&files=&repos=

Bug: T220656
Change-Id: I309ec5eebbdddd3b71541c446b15b15204abf8ca