do not stop propagation of click/focusin

the `analyzeMarkdown` function is unnecessarily stopping the propagation of all `click` and `focusin` events in the whole document, potentially breaking other functionality in the page (we had weird compatibility problems with other plugins that needed to bind on `click`).

I took the liberty to refactor the function to be much simpler and shorter and rename it `blurNonFocused`, as that's apparently what it does.