Do not show full path name in headerbar (fixes #1085)

[b-sharman]

see #1085

It looks like this for me now:

Please let me know if I've missed anything!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.67%. Comparing base (7643541) to head (af7c153).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1086   +/-   ##
=======================================
  Coverage   79.67%   79.67%           
=======================================
  Files          13       13           
  Lines        4965     4965           
=======================================
  Hits         3956     3956           
  Misses       1009     1009           

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[dreua]

The if Handy makes me wonder in which cases we don't have Handy. Are those substantial enough to reconsider this change? (Probably not, but I really don't know.)

[b-sharman]

In regards to dependence on Handy, I thought it was a little strange to check for it since non-libhandy headerbars have a set_title too. I tried setting Handy=None and removing the check like this:

    def set_title(self, title, subtitle = None):
        self.uiXML.get_object('header_bar').set_title(title)
        self.uiXML.get_object('header_bar').set_subtitle(subtitle)

and it seemed to work fine, although I'm not sure how I would test it more rigorously.

[kbengs]

I think it would be fine to remove the if Handy as @b-sharman suggest. But can be done later also.
Seems to work well.