Add option to open master branch link

[itaditya]

Hey my usecase for this plugin is that somebody wants url for a file and I'm in my editor so I can CMD + P the file and copy its link. However mostly I'm in a different branch and they won't have my branch so I have to manually change the branch name from the link to master. If in the menu there was option to Copy Online Link for master then that would be really useful.

[qinezh]

That would cause extra step to copy the link for most user scenarios, if there is an option before the copy. I would prefer to make the extension handy for most cases, instead of full functionalities.

And the request is also a little bit tricky, as the file from your branch and master branch might be different and the line number of your selection would be inaccurate and unexpected.