Update compiler/parser/src/fstring.rs

Co-authored-by: Zgarbul Andrey <zgarbul.andrey@gmail.com>

parser/src/fstring.rs

@@ -207,16 +207,14 @@ impl<'a> FStringParser<'a> {
                 '"' | '\'' => {
                     expression.push(ch);
                     loop {
-                        match self.next_char() {
+                        let Some(c) = self.next_char() else {
-                            Some(c) => {
+                            return Err(UnterminatedString);
+                        };
                         expression.push(c);
                         if c == ch {
                             break;
                         }
                     }
-                            None => return Err(UnterminatedString),
-                        }
-                    }
                 }
                 ' ' if self_documenting => {
                     trailing_seq.push(ch);