update file when switching branch

when switching branches, the file doesn't update.

The bug has been reported to the customer service of Bohemian Coding.

Meanwhile, we can probably manually trigger a reopening of the file when switching.

Start by reproducing the stale file behavior while switching branches in the Sketch plugin, then locate the branch-switching flow and the file reopening behavior. Check whether reopening can be triggered at that point, and verify that the displayed file updates after switching branches.

Written by the indexing model from the issue text.