Commit 94b296d5 changed this to
potentially insert multiple overlapping hyperlink items.

Unfortunately Writer can only have one RES_TXTATR_INETFMT on any given
position in the paragraph, so the hyperlink hints inevitably overwrite
each other.

Revert this to do it the same way as the old code in LO 4.3 did: match
the last unmatched link-start with the first link-end, and ignore all
the link-start before the matching one, as well as the link-end after
the matching one.

This should prevent surprising formatting changes on index update,
including entries spontaneously turning green, and there is no reason
why the result of the new way is objectively better than the old one.

Change-Id: I55be9c212c473908428fa8bd6487d136343fe852