fix(ruby): Use string_content capture for Ruby test name extraction

[vitallium]

Given this Ruby file:

require "test_helper"

class CategoryTest < ActiveSupport::TestCase
  context "validations" do
    should validate_presence_of(:name)
    should validate_length_of(:name).is_at_most(255)
    should validate_uniqueness_of(:name)

    should validate_presence_of(:slug)
    should validate_length_of(:slug).is_at_most(255)
    should validate_uniqueness_of(:slug)
  end
end

Attempting to run test called "validations" results in the following output:

# Running:

......

Finished in 0.196336s, 30.5599 runs/s, 30.5599 assertions/s.
6 runs, 6 assertions, 0 failures, 0 errors, 0 skips

⏵ Task `test test/models/category_test.rb -n ""validations""` finished successfully
⏵ Command: /opt/homebrew/bin/fish -i -c 'bin/rails'

With this fix:

# Running:

......

Finished in 0.212972s, 28.1727 runs/s, 28.1727 assertions/s.
6 runs, 6 assertions, 0 failures, 0 errors, 0 skips

⏵ Task `test test/models/category_test.rb -n "validations"` finished successfully
⏵ Command: /opt/homebrew/bin/fish -i -c 'bin/rails'

No changes but capturing the test name as a string without quotes gives more control over tests that, for example, use regular expressions in their names.

Closes #222