Change links from google.github.io/guava to guava.dev, including making sure they're https.

The links work even now because they automatically redirect.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=315389274

Author: cpovirk

value/userguide/builders-howto.md

@@ -335,7 +335,7 @@ public abstract class Animal {
 ```
 
 [`java.util.Optional`]: https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html
-[`com.google.common.base.Optional`]: http://google.github.io/guava/releases/snapshot/api/docs/com/google/common/base/Optional.html
+[`com.google.common.base.Optional`]: https://guava.dev/releases/snapshot/api/docs/com/google/common/base/Optional.html
 [`OptionalDouble`]: https://docs.oracle.com/javase/8/docs/api/java/util/OptionalDouble.html
 [`OptionalInt`]: https://docs.oracle.com/javase/8/docs/api/java/util/OptionalInt.html
 [`OptionalLong`]: https://docs.oracle.com/javase/8/docs/api/java/util/OptionalLong.html

value/userguide/howto.md

@@ -325,8 +325,9 @@ might be mutated and the other not.
 
 AutoValue intentionally does not provide this feature. It is better for you to
 roll your own comparison logic using the new methods added to
-[`Comparator`](https://docs.oracle.com/javase/8/docs/api/java/util/Comparator.html) in Java 8,
-or [`ComparisonChain`](http://google.github.io/guava/releases/snapshot/api/docs/com/google/common/collect/ComparisonChain.html)
+[`Comparator`](https://docs.oracle.com/javase/8/docs/api/java/util/Comparator.html)
+in Java 8, or
+[`ComparisonChain`](https://guava.dev/releases/snapshot/api/docs/com/google/common/collect/ComparisonChain.html)
 from [Guava](http://github.com/google/guava).
 
 Since these mechanisms are easy to use, require very little code, and give you