make the long file name short in the file tab

[yu2chuan]

Is your feature request related to a problem? Please describe.
It's good to open multiple md files. However, it's hard to transition to the other file if one of them has a very long file name.

Describe the solution you'd like
When the md file name is longer than a certain number of characters, the markflow only shows one-third of the file name in the file tab. 
You may have the other better idea.

Describe alternatives you've considered

Additional context

[drl990114]

Good suggestion, I think your suggestion is good