How do I history search an OSM Wiki page?

See https://lists.openstreetmap.org/pipermail/tagging/2015-May/024339.html : "actually wikiblame apparently works out of the box if you know which parameters to enter".

So, we can use Flominator's WikiBlame (with parameters set for the OpenStreetMap wiki). You just need to enter the "page" and "search for" boxes and press start.

Example:

It found the correct addition diff for the example search.

I am not aware of tools for this.

You can do a manual binary search through the history (clicking the diff links and check if your target sentence is present on the page while using a version selection approximately according to the binary search algorithm). This is what I sometimes do.

You could look at the full page history and select the version that is half way between the oldest and newest page to see if the specific sentence you are looking for was added before or after that version. Then repeat the process in the half of the history where the specific sentence appears to have been added. This can be a bit of a laborious process if there are hundreds of edits but with this sort of binary search you should only need to look at a dozen versions of the page even if it was edited a thousand times.

Also, if you click on the "cur" link for a version you can see how the historic version differs from the current version. If you click on the "prev" link for a version you can see what changes were made to create that version. If you click on the radio buttons of two versions and then click "Compare selected revisions" you can see the changes made between two versions of a page. Helpfully, the difference pages allow you to step back and forth to see the differences between earlier and later revisions too. You might also find the edit comments will assist you identifying the version, as you might find when a section was added.

I know this might still seem a rather tedious method but it is faster than stepping though each revision of a page, revision by revision.