helix-term: Update test to not use absent partial history

helix-term/tests/test/prompt.rs

@@ -4,7 +4,7 @@ use super::*;
 async fn test_history_completion() -> anyhow::Result<()> {
     test_key_sequence(
         &mut AppBuilder::new().build()?,
-        Some(":asdf<ret>:theme d<C-n><tab>"),
+        Some(":asdf<ret>:<C-n><tab>"),
         Some(&|app| {
             assert!(!app.editor.is_err());
         }),