Since "nbsp" is hard to translate, it is removed from the current
text of visualeditor-mwlanguagevariantcontextitem-rule-code-label,
which was "Language code" - now changed to "Language code".
Instead the table headings (where this message is used) are defined
as non-breaking in CSS.
Bug: T173181
Change-Id: I9794fa010ad908fe772fa6858c25acc6beb973d5