Temporarily fix multi-paragraph definition lists

The rdoc markdown parser does not currently parse multi-paragraph
definition lists correctly. Instead of putting both paragraphs inside
a single definition, only the first paragraph ends up in the definition
and the second paragraph is rendered after the definition list as a code
block.

Since 7.2 appears to be coming soon, this commit fixes the second
paragraph rendering as a code block by turning it into a second
definition. This doesn't strictly seem like the "correct" fix (compared
to fixing the rdoc markdown parser) but it gives us the visual result
that we want until rdoc is fixed.

Author: skipkayhil

actionpack/lib/action_controller/metal/conditional_get.rb

@@ -48,7 +48,7 @@ def etag(&etagger)
     #     `If-None-Match` header may receive a `304 Not Modified` response if the
     #     ETag matches exactly.
     #
-    #     A weak ETag indicates semantic equivalence, not byte-for-byte equality, so
+    # :   A weak ETag indicates semantic equivalence, not byte-for-byte equality, so
     #     they're good for caching HTML pages in browser caches. They can't be used
     #     for responses that must be byte-identical, like serving `Range` requests
     #     within a PDF file.
@@ -58,7 +58,7 @@ def etag(&etagger)
     #     `If-None-Match` header may receive a `304 Not Modified` response if the
     #     ETag matches exactly.
     #
-    #     A strong ETag implies exact equality -- the response must match byte for
+    # :   A strong ETag implies exact equality -- the response must match byte for
     #     byte. This is necessary for serving `Range` requests within a large video
     #     or PDF file, for example, or for compatibility with some CDNs that don't
     #     support weak ETags.