Warn if editing a symlink (BB-9985)
sym-links are represented as normal files with special attributes in Mercurial.
In Bitbucket, this is not easy to spot. With the recently introduced editor it is easy to edit such a "symlink file" without knowing that this is represents a symlink.
Either prevent the editing of symlink files completely or at least display a warning that one is currently editing a symlink and not a regular file.