Tweak regexp such that a trailing ":" is not included in the file path
extracted from a lazygit-edit URL.
Previously, when matching a URL containing the ":" separator but no line
number, such as `lazygit-edit:///path/to/file.ext:`, the trailing
separator would be included in the matched file path, so lazygit would
open the non-existent file `/path/to/file.ext:`. Notably, such urls are
created when using delta with the hyperlink feature, as suggested in
https://github.com/jesseduffield/lazygit/blob/master/docs/Custom_Pagers.md#delta,
and clicking a file path rather than a line number.
