Space before colon gets rendered as `<span> </span>` when wrapped in a reference. Clearly somehow related to {T94509}. Example: http://en.wikipedia.beta.wmflabs.org/w/index.php?title=French_colon&diff=216680&oldid=216679
To reproduce:
* Have a wikitext page with `foo : bar`. (It won't work if you just type that on a page, it must go through Parsoid.)
* In VisualEditor, select that text, insert a basic reference, and paste it inside.
* Save the page. Result: `<ref>foo<span> </span>: bar</ref>`
Originally reported by @NicoV at T96589:
https://fr.wikipedia.org/w/index.php?title=Lyc%C3%A9e_Paul_Eluard&diff=prev&oldid=113829511
https://fr.wikipedia.org/w/index.php?title=Lyc%C3%A9e_Paul_Eluard&diff=prev&oldid=113829346
https://fr.wikipedia.org/w/index.php?title=Lyc%C3%A9e_Paul_Eluard&diff=prev&oldid=113828982