so many error cases.

src/bin/ngri.rs

@@ -16,18 +16,30 @@ fn main() -> Result<(), BackendError> {
                 ":quit" => break,
                 _ => state.process_input(line_no, command),
             },
+
+            // it's not clear to me what this could be, but OK
             Err(ReadlineError::Io(e)) => {
                 eprintln!("IO error: {}", e);
                 break;
             }
+
+            // Control-D and Control-C
             Err(ReadlineError::Eof) => break,
             Err(ReadlineError::Interrupted) => break,
+
+            // For some reason this doesn't exist on Windows. I also don't quite know
+            // what would cause this, but ...
             #[cfg(not(windows))]
             Err(ReadlineError::Errno(e)) => {
                 eprintln!("Unknown syscall error: {}", e);
                 break;
             }
+
+            // We don't actually do any reflow-ing if we change the terminal size,
+            // so we can just ignore this.
             Err(ReadlineError::WindowResized) => continue,
+
+            // Why on earth are there so many error types?
             Err(e) => {
                 eprintln!("Unknown internal error: {}", e);
                 break;