parser: add Builders::Default#value, string_value and loc

[apiology]

Claude: This PR was written by Claude Code on behalf of @apiology.

Problem:

A Parser::Builders::Default subclass gets untyped back from value, and cannot call string_value or loc:

class FlawedBuilder < ::Parser::Builders::Default
  # @param token [Array(String, ::Parser::Source::Range)]
  # FlawedBuilder#string_value return type could not be inferred
  def string_value token
    value(token)
  end
end

class TestBuilder < Parser::Builders::Default
  def token_loc(range)
    # test.rb:89:4: [error] Type `::TestBuilder` does not have method `loc`
    loc(["foo", range])&.source
  end
end

The parser RBS has no Builders::Default signatures, so every builder subclass loses the token's type.

Solution:

Add private value: [T] ([T, Source::Range] token) -> T, string_value: ([String, Source::Range] token) -> String and loc: ([top, Source::Range]? token) -> Source::Range?, matching value, string_value and loc in parser v3.3.12.0.

[github-actions]

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See also: https://github.com/ruby/gem_rbs_collection/blob/main/docs/CONTRIBUTING.md

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parser

You changed RBS files for an existing gem.
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@pocke, @kozy4324, please review this pull request.
If this change is acceptable, please make a review comment including APPROVE from here.

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[kozy4324]

APPROVE

[github-actions]

Thanks for your review, @kozy4324!

@apiology, @kozy4324 This PR is ready to be merged.
Just comment /merge to merge this PR.

[apiology]

/merge