Add rewrite_methods to Redefiner, replacing untyped_methods when type checking is off

[obsidiannnn]

Summary

Implements rewrite_methods in Low::Redefiner as the new code path when
LowType.config.type_checking is false. Foundational piece for #38.

Changes

lib/definitions/redefiner.rb

• Added rewrite_methods - calls method_proxy.rewrite_signature to strip type
  annotations from the shared lines array, then uses klass.class_eval(method_proxy.export)
  to redefine the method directly on the class
• Preserves private visibility for methods below private_start_line
• redefine now accepts optional klass: keyword and routes to rewrite_methods
  when type checking is off

lib/low_type.rb

• Both redefine calls now pass klass: through
• Result guarded with if result since rewrite_methods returns nil, not a Module

Depends on

• Add export(typed: false) to ParamProxy and rewrite_signature to MethodProxy lowkey#9 (ParamProxy#export(typed: false) and MethodProxy#rewrite_signature)

Tests

122 examples, 0 failures