cli: print success to console on `rad issue state`

Indicate that the `rad issue state` operation was successful to the
user by printing a message to the console.

Solves:

    rad issue show 71020de8478b15b3f7a619f2f93d3cfb8771cde2

radicle-cli/examples/workflow/5-patching-maintainer.md

@@ -123,3 +123,12 @@ To publish our new state to the network, we simply push:
 ```
 $ git push
 ```
+
+Finally, we will close the issue that was opened for this
+patch, marking it as solved:
+
+```
+$ rad issue state 9037b7a --solved
+✓ Issue 9037b7a is now solved
+✓ Synced with 1 node(s)
+```

radicle-cli/src/commands/issue.rs

@@ -567,6 +567,17 @@ pub fn run(options: Options, ctx: impl term::Context) -> anyhow::Result<()> {
             let id = id.resolve(&repo.backend)?;
             let mut issue = issues.get_mut(&id)?;
             issue.lifecycle(state, &signer)?;
+            if !options.quiet {
+                let success =
+                    |status| term::success!("Issue {} is now {status}", term::format::cob(&id));
+                match state {
+                    State::Closed { reason } => match reason {
+                        CloseReason::Other => success("closed"),
+                        CloseReason::Solved => success("solved"),
+                    },
+                    State::Open => success("open"),
+                };
+            }
         }
         Operation::React {
             id,