Hide all lines from pull request file

Hi there,

For some pull requests, there are long boilerplate files that nevertheless must be committed. It would be nice to have for the web interface, in the settings menu for that file, to be able to collapse all of the code lines in that file so that the only thing visible is the filename header that contains menu options for that file. I have included an image to make clear what I mean by "file header".

Thanks,
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