api: replaced formatting with fstrings

rhodecode/api/__init__.py

@@ -392,7 +392,7 b' class RoutePredicate(object):'
         self.val = val
 
     def text(self):
-        return 'jsonrpc route = %s' % self.val
+        return f'jsonrpc route = {self.val}'
 
     phash = text
 
@@ -412,7 +412,7 b' class NotFoundPredicate(object):'
         self.methods = config.registry.jsonrpc_methods
 
     def text(self):
-        return 'jsonrpc method not found = {}.'.format(self.val)
+        return f'jsonrpc method not found = {self.val}'
 
     phash = text
 
@@ -425,7 +425,7 b' class MethodPredicate(object):'
         self.method = val
 
     def text(self):
-        return 'jsonrpc method = %s' % self.method
+        return f'jsonrpc method = {self.method}'
 
     phash = text