Function to adjust the name of a Rule, GRuleDef, GRuleCall and Named Group

[aniketd]

With the ability to rename an existing definition one would not need to redefine an entire rule, just to use it with a different name.

For examples:

aSimpleRule :: Rule
aSimpleRule = "a_simple_rule" =:= VUInt

...could be reused in another file as

aSimpleRuleRenamed :: Rule
aSimpleRuleRenamed = aSimpleRule `renamedAs` $ \n -> n <> "_with_a_new_suffix"

This can probably be achieved by a combination of {get|set}Field.