chore: link "name", Resource Name, to its AIP (aip-dev#851)

Updates the md for AIP-180 so that "name" under the "Changing resource names" section is linked to the "Resource names" AIP, AIP-122, so that it makes it clearer, at least by inference, that "name" refers to the Resource Name, e.g. `locations/:location/project/:projectId/books/:bookId`, and not the name of the proto that represents the Resource, e.g. `message Book`. This was not clear to this reader, when reading the paragraph, at first.

aip/general/0180.md

@@ -99,7 +99,7 @@ breaking way.
 
 ### Changing resource names
 
-A resource **must not** change its name.
+A resource **must not** change its [name][aip-122].
 
 Unlike most breaking changes, this affects major versions as well: in order for
 a client to expect to use v2.0 access a resource that was created in v1.0 or
@@ -141,6 +141,7 @@ this guidance could ostensibly prevent _any_ change (which is not the intent).
   breaking.
 
 <!-- prettier-ignore-start -->
+[aip-122]: ./0122.md
 [aip-158]: ./0158.md
 [aip-181]: ./0181.md
 [ec2]: https://aws.amazon.com/blogs/aws/theyre-here-longer-ec2-resource-ids-now-available/