Sizzle: work with selectors ending with space
Sizzle: work with selectors ending with space

When using Sizzle `:first` selector is added to user-passed selector
to emulate `querySelector`.
If selector string ends with space, incorrect selector was formed and
wrong element was used.
Fixed by trimming the selector string.

racing-post/gemini,varya/gemini,HDevel/gemini,pazone/gemini,sergesemashko/gemini,racing-post/gemini,gemini-testing/gemini,vladislav-sevostyanov/gemini,HDevel/gemini,pazone/gemini,varya/gemini