As a Lexeme editor I want to save a Lemma using only the keyboard.

Problem:
When editing a Lemma, pressing enter does nothing. It should save the changes, like it does elsewhere.

Example:
https://www.wikidata.org/wiki/Lexeme:L123

BDD
GIVEN a Lexeme Lemma
WHEN in edit mode
AND I make a change to Lemma, Spelling variant, Language or Lexical Category
AND the focus is in the Lemma, Spelling variant, Language or Lexical Category field
AND I press Enter
THEN the change is saved

Acceptance criteria:

• pressing enter in the Lemma, Spelling variant, Language or Lexical Category field of a Lexeme saves the input

Notes:

• The right thing already happens for the representation and spelling variant of Forms.