Refactor ruff_cli's run method to return on each branch (#7040)

## Summary

I think the fallthrough here for some branches is a little confusing.
Now each branch either runs a command that returns `Result<ExitStatus>`,
or runs a command that returns `Result<()>` and then explicitly returns
`Ok(ExitStatus::SUCCESS)`.

crates/ruff_cli/src/commands/config.rs

@@ -1,19 +1,19 @@
-use crate::ExitStatus;
+use anyhow::{anyhow, Result};
+
 use ruff_workspace::options::Options;
 
 #[allow(clippy::print_stdout)]
-pub(crate) fn config(key: Option<&str>) -> ExitStatus {
+pub(crate) fn config(key: Option<&str>) -> Result<()> {
     match key {
         None => print!("{}", Options::metadata()),
         Some(key) => match Options::metadata().get(key) {
             None => {
-                println!("Unknown option");
-                return ExitStatus::Error;
+                return Err(anyhow!("Unknown option: {key}"));
             }
             Some(entry) => {
                 print!("{entry}");
             }
         },
     }
-    ExitStatus::Success
+    Ok(())
 }