Adjust existing test case to reflect current functional behavior change

Author: rami3l

tests/suite/cli_v2.rs

@@ -1067,7 +1067,11 @@ fn update_unavailable_force() {
         config.expect_err(
             &["rustup", "update", "nightly"],
             for_host!(
-                "component 'rls' for target '{0}' is unavailable for download for channel 'nightly'"
+                r"error: component 'rls' for target '{0}' is unavailable for download for channel 'nightly'
+Sometimes not all components are available in any given nightly. If you are trying to update an existing toolchain and no longer need this component,
+you might want to remove it first with:
+
+    rustup component remove --toolchain nightly --target {0} rls"
             ),
         );
         config.expect_ok(&["rustup", "update", "nightly", "--force"]);