Highlight .ipynb files

It would be better if the jupyter notebook files(.ipynb) are highlighted while browsing the files in the browser. Or else a search feature is added like the github file finder. Helps in case there are a lot of other files.

Start by locating the browser file-listing entry point and review how .ipynb files are currently displayed. Use the GitHub file finder mentioned in the issue as a reference, then clarify whether the desired outcome is highlighting notebook files, adding search, or both; done means the chosen behavior works when browsing many files.

Written by the indexing model from the issue text.