Minor improvements

Closes: https://github.com/sayanarijit/xplr/issues/305

src/app.rs

@@ -1582,7 +1582,7 @@ impl App {
 
         let pid = std::process::id();
         let session_path = dirs::runtime_dir()
-            .unwrap_or_else(|| "/tmp".into())
+            .unwrap_or_else(env::temp_dir)
             .join("xplr")
             .join("session")
             .join(&pid.to_string())

src/bin/xplr.rs

@@ -78,7 +78,7 @@ impl Cli {
 
 fn main() {
     let cli = Cli::parse(env::args()).unwrap_or_else(|e| {
-        println!("error: {}", e);
+        eprintln!("error: {}", e);
         std::process::exit(1);
     });