Fix scope chain traversal in variable definition lookup

[Copilot]

Method parameters and local variables were not found during definition lookup because scope_definitions_for only checked the innermost scope repeatedly instead of walking the scope chain.

Root Cause

The while loop incremented check_scope to traverse parent scopes but always queried scope.variables:

while check_scope
  scope.variables.each do |variable|  # Always queries the same scope
    # ...
  end
  check_scope = check_scope.parent
end

This caused lookups to miss variables in the current scope when searching from within nested contexts.

Changes

• lib/ruby_language_server/project_manager.rb: Changed scope.variables.each to check_scope.variables.each to properly traverse the scope chain
• spec/lib/ruby_language_server/project_manager_spec.rb: Added test covering parameter shadowing scenario from issue

Original prompt

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This section details on the original issue you should resolve

<issue_title>method variables not getting used for definition locating</issue_title>
<issue_description>If you have the following:

class Foo
  def meaningful ...
end

class Bar
  def some_method(meaningful)
    meaningful.do_something
  end
end

When you look for the definition of meaningfujl in some_method, it should find the local declaration. It does not - it only finds the method defined in class Foo.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes method variables not getting used for definition locating #118

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