Fix issues with default parameters in functions and classes

Default parameters were resolved at the wrong starting position. Fixes #1044

test/completion/functions.py

@@ -201,6 +201,9 @@ def default_function(a=default):
 #? int()
 default_function()
 
+def default(a=default):
+    #? int()
+    a
 
 # -----------------
 # closures