Convert formatting automatically to f-strings

Automatically convert formatting with the following call:
flynt -ll 2000 -v frappy*
Result: 303/381 auto-converted.
Failing conversions will be looked at manually in a follow-up commit.

Change-Id: Icd996b27221202faccc15af78e0380cf52ee37f2
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/30900
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Georg Brandl <g.brandl@fz-juelich.de>
Reviewed-by: Alexander Zaft <a.zaft@fz-juelich.de>

frappy/rwhandler.py

@@ -87,7 +87,7 @@ class Handler:
         if (func.__module__, func.__qualname__) in self.method_names:
             # make sure method name is not used twice
             # (else __set_name__ will not be called)
-            raise ProgrammingError('duplicate method %r' % func.__qualname__)
+            raise ProgrammingError(f'duplicate method {func.__qualname__!r}')
         self.func = func
         func.wrapped = False
         self.method_names.add((func.__module__, func.__qualname__))
@@ -113,8 +113,8 @@ class Handler:
                 wrapped.poll = getattr(wrapped, 'poll', self.poll)
             func = getattr(owner, method_name, None)
             if func and method_name in owner.__dict__:
-                raise ProgrammingError('superfluous method %s.%s (overwritten by %s)'
-                                       % (owner.__name__, method_name, self.__class__.__name__))
+                raise ProgrammingError(f'superfluous method {owner.__name__}.' \
+                                       f'{method_name} (overwritten by {self.__class__.__name__})')
             setattr(owner, method_name, wrapped)
 
     def wrap(self, key):