Remove an old comment about overriding the location of JDK Javadoc under Java 8.

We started doing that in cl/272937179 but then stopped in 54ec670, and I neglected to remove this comment at that point.

It's possible that we "should" instead _restore_ the override, since JDK links might not work when I run with `JAVA_HOME` pointing to Java 8:

```
[WARNING] Javadoc Warnings
[WARNING] javadoc: warning - Error fetching URL: https://guava.dev/releases/33.5.0-jre/api/docs/
[WARNING] javadoc: warning - Error fetching URL: https://docs.oracle.com/en/java/javase/11/docs/api/
```

However:
- I doubt we'd build a release with Java 8 nowadays.
  - javadoc.io doesn't seem to, either: I see working links for types like `String` in https://javadoc.io/doc/com.google.jimfs/jimfs/1.3.1/com/google/common/jimfs/AttributeProvider.html.
- If we do build a release with Java 8, and if that does indeed break links, then I'd expect it to break links to Guava, too, as indicated by the additional warning above. So that's another reason to just Not Do That.

All that said: The real motivation here is _still_ to test Copybara, this time after cl/813878868.

RELNOTES=n/a
PiperOrigin-RevId: 813892137

Author: cpovirk

pom.xml

@@ -167,7 +167,6 @@
             <links>
               <link>https://guava.dev/releases/${guava.version}/api/docs/</link>
               <link>https://unicode-org.github.io/icu-docs/apidoc/released/icu4j</link>
-              <!-- When building against Java 8, the Java 11 link below is overridden to point to an older version (Java 9, the newest one that works). -->
               <link>https://docs.oracle.com/en/java/javase/11/docs/api/</link>
             </links>
           </configuration>