Support entities inside text content

When writing something like:

> When ranking for sentiment on the other hand, [[subgrid]] turned out to be the most loved feature, with 51.5% of respondents willing to use it again.

Replace `[[subgrid]]` with the corresponding Subgrid entity item, inline with the rest of the text:

Start by locating the code that renders text content and the Subgrid entity data. Reproduce the example from the issue, then trace how entity references are represented and rendered inline. Done means [[subgrid]] is replaced by the corresponding Subgrid entity item within the surrounding text, matching the screenshot.

Written by the indexing model from the issue text.