Add reference to block in pages that were linked.

[gmierz]

This patch adds a new feature that adds a reference of the block that links were produced for into the pages that were found. A new setting is added for it called referenceInPages and is disabled by default. Tests were also modified as the pages found needed to be returned from the replaceContentWithPageLinks function.

[gmierz]

Hi @sawhney17, I've been really enjoying using your plugin! One thing that I found was missing from it is the ability to add the blocks that links were produced for into the pages that were found in it. For example, if a block in the journal mentions a linked page like Logseq, then in the Logseq page a new block reference would be added for the block that was parsed to create the link. Let me know what you think about it.