Use Display for formatter parse errors (#9316)

## Summary

This helps a bit with (but does not close) the issues described in
https://github.com/astral-sh/ruff/issues/9311. E.g., now, we at least
see: `error: Failed to format main.py: source contains syntax errors:
invalid syntax. Got unexpected token '=' at byte offset 20`.

crates/ruff_python_parser/src/lexer.rs

@@ -1308,6 +1308,31 @@ impl LexicalError {
     }
 }
 
+impl std::ops::Deref for LexicalError {
+    type Target = LexicalErrorType;
+
+    fn deref(&self) -> &Self::Target {
+        &self.error
+    }
+}
+
+impl std::error::Error for LexicalError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        Some(&self.error)
+    }
+}
+
+impl std::fmt::Display for LexicalError {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "{} at byte offset {}",
+            &self.error,
+            u32::from(self.location)
+        )
+    }
+}
+
 /// Represents the different types of errors that can occur during lexing.
 #[derive(Debug, Clone, PartialEq)]
 pub enum LexicalErrorType {
@@ -1350,6 +1375,8 @@ pub enum LexicalErrorType {
     OtherError(String),
 }
 
+impl std::error::Error for LexicalErrorType {}
+
 impl std::fmt::Display for LexicalErrorType {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self {

crates/ruff_python_parser/src/parser.rs

@@ -305,12 +305,6 @@ impl fmt::Display for ParseError {
     }
 }
 
-impl ParseError {
-    pub fn error(self) -> ParseErrorType {
-        self.error
-    }
-}
-
 /// Represents the different types of errors that can occur during parsing.
 #[derive(Debug, PartialEq)]
 pub enum ParseErrorType {