Linking to a line of code with single-file (file-by-file) mode enabled fails to load the file if it's not already in memory

The title is a bit long but it describes the whole problem:

1. In single-file view mode
2. If the MR has not already loaded a file (e.g. it's been automatically truncated for size or MR length)
3. When visiting a particular line of code
4. The file fails to load

There is an error in the console related to the Super Sidebar. This doesn't seem related at first glance.

The problem is that the code that parses the URL to determine which file to load doesn't understand all forms of file identifiers (due to an incorrect RegExp searching for word boundaries that often won't exist).