html.lang: Remove unallowed whitespace
html.lang: Remove unallowed whitespace

* In start tags, there cannot be whitespace between the less-than and
the tag name
* In end tags, there cannot be whitespace between the less-than, slash,
and the tag name
* Comments must end with "-->" (no space allowed between "--" and ">")

https://html.spec.whatwg.org/multipage/syntax.html#start-tags
https://html.spec.whatwg.org/multipage/syntax.html#end-tags
https://html.spec.whatwg.org/multipage/syntax.html#comments

GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview,GNOME/gtksourceview