fix: remove backslash in multi-line input (#832)

Author: brandonskiser

crates/q_cli/src/cli/chat/input_source.rs

@@ -46,6 +46,7 @@ impl InputSource {
                                 continue;
                             } else if l.ends_with("\\") {
                                 line.push_str(&l);
+                                line.pop();
                                 prompt = ">> ";
                                 continue;
                             } else {