Revert "added hint for multiline triple backtick code block detector (#3327)" (#3439)

This reverts commit 2d16273.

Author: dingfeli

crates/chat-cli/src/cli/chat/prompt.rs

@@ -353,16 +353,6 @@ impl ChatHinter {
             return None;
         }
 
-        // Check for unclosed triple backticks
-        if line.contains("```") {
-            let triple_backtick_count = line.matches("```").count();
-            if triple_backtick_count % 2 == 1 {
-                // We have an odd number of ```, meaning we're in multiline mode
-                // Show status hint (right arrow key is overridden to not complete this)
-                return Some("in multiline mode, waiting for closing backticks ```".to_string());
-            }
-        }
-
         // If line starts with a slash, try to find a command hint
         if line.starts_with('/') {
             return self
@@ -560,34 +550,6 @@ impl rustyline::ConditionalEventHandler for PasteImageHandler {
     }
 }
 
-/// Handler for right arrow key that prevents completing the multiline status hint
-struct RightArrowHandler;
-
-impl rustyline::ConditionalEventHandler for RightArrowHandler {
-    fn handle(
-        &self,
-        _evt: &rustyline::Event,
-        _n: rustyline::RepeatCount,
-        _positive: bool,
-        ctx: &rustyline::EventContext<'_>,
-    ) -> Option<Cmd> {
-        let line = ctx.line();
-
-        // Check if we're in multiline mode with unclosed backticks
-        if line.contains("```") {
-            let triple_backtick_count = line.matches("```").count();
-            if triple_backtick_count % 2 == 1 {
-                // We're in multiline mode - don't complete the hint
-                // Just move the cursor forward instead
-                return Some(Cmd::Move(rustyline::Movement::ForwardChar(1)));
-            }
-        }
-
-        // Normal case - complete the hint
-        Some(Cmd::CompleteHint)
-    }
-}
-
 pub fn rl(
     os: &Os,
     sender: PromptQuerySender,
@@ -681,12 +643,6 @@ pub fn rl(
         EventHandler::Conditional(Box::new(PasteImageHandler::new(paste_state))),
     );
 
-    // Override right arrow key to prevent completing multiline status hints
-    rl.bind_sequence(
-        KeyEvent(KeyCode::Right, Modifiers::empty()),
-        EventHandler::Conditional(Box::new(RightArrowHandler)),
-    );
-
     Ok(rl)
 }