To avoid being able to introduce dependencies between tests this commit
makes sure that we close the document between tests so that we can't
accidentally rely on state set by a previous test.
The current logic assumes that all spans in the text layer contain
only one text node, and thus that the position information
returned by `highlighter._convertMatches` can be directly used
on the element's only child.
This is not true in case of highlighted search results: they will be
injected in the DOM as `<span>` elements, causing the `<span>`s
in the text layer to have more than one child.
This patch fixes the problem by properly converting the (span, offset)
pair in a (textNode, offset) pair that points to the right text node.
*Note:* For the issue mentioned on Matrix it'll obviously still make sense to improve the regular expression to detect more URL edge-cases.
However it occurred to me that even once that particular case is fixed there'll always be a risk that inferred links could overlap, and effectively block, the actual LinkAnnotations.
Hence this patch removes the URL comparison to ensure that overlapping inferred links will always be ignored.
Automatically detect links in the text content of a file and automatically
generate link annotations at the appropriate locations to achieve
automatic link detection and hyperlinking.
