Refactor: convert_offset take owned u32

crates/oxc_ast/src/utf8_to_utf16.rs

@@ -47,16 +47,18 @@ impl Utf8ToUtf16 {
     }
 
     fn convert_span(&self, span: &mut Span) {
-        self.convert_offset(&mut span.start);
-        self.convert_offset(&mut span.end);
+        span.start = self.convert_offset(span.start);
+        span.end = self.convert_offset(span.end);
     }
 
-    fn convert_offset(&self, utf8_offset: &mut u32) {
+    fn convert_offset(&self, utf8_offset: u32) -> u32 {
         // FIXME:
-        let index = self.utf8_offsets.partition_point(|offset| offset < utf8_offset);
-        if let Some(utf16_difference) = self.utf16_differences.get(index) {
-            *utf8_offset -= utf16_difference;
+        let mut utf16_offset = utf8_offset;
+        let index = self.utf8_offsets.partition_point(|&offset| offset < utf8_offset);
+        if let Some(&utf16_difference) = self.utf16_differences.get(index) {
+            utf16_offset -= utf16_difference;
         }
+        utf16_offset
     }
 }