I think it would be extremely helpful to have some sort of "find" ability to be able to locate code you know you typed but the app is too big to efficiently look for. It would enable one to see all the places a certain syntax or operator was used.
One specific use-case that comes to mind is making the app more efficient after learning awesome new tips from @mdevaney or @RezaDorrani or @SanchoHarker, among many others. If I could find all the places I used, say, ForAll, I could easily replace the instances with the much more efficient method suggested by the many wonderful community stars we have.
Another would be changing the all SharePoint column names after a back-end change is made.