Enable internal search feature in CodeMirror area of Overpass-Turbo web UI

[MurzNN]

At now it's impossible to find something in Data tab via browser search, if result have scroll and search string is not displayed in current view area. This is because it uses CodeMirror, that seems do lazy-render for only visible part of data output into browser HTML, so browser do the search only in visible part of result data not inside whole result.

For solve this problem, will be good to enable internal search feature in CodeMirror of Overpass-Turbo web UI at https://overpass-turbo.eu/, here is example of it: https://codemirror.net/demo/search.html