Add notes on how to configure the virtual workspace's resolver

Author: Nemo157

src/cargo/core/workspace.rs

@@ -1010,6 +1010,10 @@ impl<'cfg> Workspace<'cfg> {
                      \x20   specify the desired resolver version explicitly in the workspace root's manifest\
                             ",
                         ))?;
+                        self.config.shell().note(
+                            "to keep the current resolver, specify `workspace.resolver = \"1\"`",
+                        )?;
+                        self.config.shell().note(format_args!("to use the edition {edition} resolver, specify `workspace.resolver = \"{resolver}\"`"))?;
                     }
                 }
             }

tests/testsuite/features2.rs

@@ -1434,6 +1434,8 @@ fn edition_2021_workspace_member() {
 warning: some crates are on edition 2021 which defaults to `resolver = \"2\"`,
     but virtual workspaces default to `resolver = \"1\"`
     specify the desired resolver version explicitly in the workspace root's manifest
+note: to keep the current resolver, specify `workspace.resolver = \"1\"`
+note: to use the edition 2021 resolver, specify `workspace.resolver = \"2\"`
 [CHECKING] a v0.1.0 [..]
 [FINISHED] [..]
 ",