Small doc fixes

[ci skip]

actionmailer/lib/action_mailer/test_helper.rb

@@ -115,7 +115,7 @@ def assert_enqueued_emails(number, &block)
     #     end
     #   end
     #
-    # If `args` is provided as a Hash, a parameterized email is matched.
+    # If +args+ is provided as a Hash, a parameterized email is matched.
     #
     #   def test_parameterized_email
     #     assert_enqueued_email_with ContactMailer, :welcome,

actionpack/lib/action_dispatch/routing/url_for.rb

@@ -204,7 +204,7 @@ def full_url_for(options = nil) # :nodoc:
       #   end
       #
       # This maintains the context of the original caller on
-      # whether to return a path or full url, e.g:
+      # whether to return a path or full URL, e.g:
       #
       #   threadable_path(threadable)  # => "/buckets/1"
       #   threadable_url(threadable)   # => "http://example.com/buckets/1"

actionview/lib/action_view/helpers/asset_tag_helper.rb

@@ -105,7 +105,7 @@ def javascript_include_tag(*sources)
       # to "screen", so you must explicitly set it to "all" for the stylesheet(s) to
       # apply to all media types.
       #
-      # If the server supports Early Hints header links for these assets  will be
+      # If the server supports Early Hints header links for these assets will be
       # automatically pushed.
       #
       #   stylesheet_link_tag "style"

activesupport/lib/active_support/test_case.rb

@@ -43,23 +43,23 @@ def test_order
 
       # Parallelizes the test suite.
       #
-      # Takes a `workers` argument that controls how many times the process
+      # Takes a +workers+ argument that controls how many times the process
       # is forked. For each process a new database will be created suffixed
       # with the worker number.
       #
       #   test-database-0
       #   test-database-1
       #
-      # If `ENV["PARALLEL_WORKERS"]` is set the workers argument will be ignored
+      # If <tt>ENV["PARALLEL_WORKERS"]</tt> is set the workers argument will be ignored
       # and the environment variable will be used instead. This is useful for CI
       # environments, or other environments where you may need more workers than
       # you do for local testing.
       #
-      # If the number of workers is set to `1` or fewer, the tests will not be
+      # If the number of workers is set to +1+ or fewer, the tests will not be
       # parallelized.
       #
       # The default parallelization method is to fork processes. If you'd like to
-      # use threads instead you can pass `with: :threads` to the `parallelize`
+      # use threads instead you can pass <tt>with: :threads</tt> to the +parallelize+
       # method. Note the threaded parallelization does not create multiple
       # database and will not work with system tests at this time.
       #