remote: remote_http_cache flag renamed to remote_cache

* the change is backward compatible
* `remote_http_cache` flag is now deprecated
* `remote_rest_cache` is now removed (has been deprecated for over a year)
* `remote_cache` flag to be used in the following format: `(http|https|grpc)://host:port`
* for backward compatibility, missing protocol in `remote_cache` defaults to 'grpc'

Closes #7897.

PiperOrigin-RevId: 241724021
diff --git a/site/docs/remote-caching-debug.md b/site/docs/remote-caching-debug.md
index 3d62f55..46d0e77 100644
--- a/site/docs/remote-caching-debug.md
+++ b/site/docs/remote-caching-debug.md
@@ -75,8 +75,8 @@
 
    a. Since cache-reading Bazel invocations will have a different command-line set
       up, take additional care to ensure that they are properly set up to
-      communicate with the remote cache. Ensure `--remote_cache` or
-      `--remote_http_cache` flags are set and there are no warnings in the output.
+      communicate with the remote cache. Ensure the `--remote_cache` flag is set
+      and there are no warnings in the output.
 
    b. Ensure your cache-reading Bazel invocations build the same targets as the
       cache-writing Bazel invocations.