Resolve Upgrading Rails lint violation

Follow-up to [#49474][]

Execute documentation change in CI so that the linters can scan the
documentation's code blocks.

[#49474]: #49474 (comment)

guides/source/upgrading_ruby_on_rails.md

@@ -266,7 +266,7 @@ responds to various format methods (for example, `rendered.html` and
 test. For example, the following [assert_match][] assertion will pass:
 
 ```ruby
-assert_match /some content/i, rendered
+assert_match(/some content/i, rendered)
 ```
 
 However, if your tests rely on `ActionView::TestCase#rendered` returning an
@@ -283,7 +283,6 @@ end
 
 [assert_match]: https://docs.seattlerb.org/minitest/Minitest/Assertions.html#method-i-assert_match
 
-
 Upgrading from Rails 6.1 to Rails 7.0
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