pkg/string_scanner: code format, expanded dependency constraint on unittest

lib/src/line_scanner.dart

Index: lib/src/line_scanner.dart
diff --git a/lib/src/line_scanner.dart b/lib/src/line_scanner.dart
index 4e1217305bbf66237df323972cd4cd7c6b6b939a..54ecf7bf9e62215d7a7412a760a24fb1b5dae60d 100644
--- a/lib/src/line_scanner.dart
+++ b/lib/src/line_scanner.dart
@@ -40,8 +40,8 @@ class LineScanner extends StringScanner {
     super.position = newPosition;
 
     if (newPosition > oldPosition) {
-      var newlines = "\n".allMatches(string.substring(oldPosition, newPosition))
-          .toList();
+      var newlines =
+          "\n".allMatches(string.substring(oldPosition, newPosition)).toList();
       _line += newlines.length;
       if (newlines.isEmpty) {
         _column += newPosition - oldPosition;
@@ -49,8 +49,8 @@ class LineScanner extends StringScanner {
         _column = newPosition - newlines.last.end;
       }
     } else {
-      var newlines = "\n".allMatches(string.substring(newPosition, oldPosition))
-          .toList();
+      var newlines =
+          "\n".allMatches(string.substring(newPosition, oldPosition)).toList();
       _line -= newlines.length;
       if (newlines.isEmpty) {
         _column -= oldPosition - newPosition;
@@ -75,7 +75,6 @@ class LineScanner extends StringScanner {
   }
 
   bool scan(Pattern pattern) {
-    var oldPosition = position;
     if (!super.scan(pattern)) return false;
 
     var newlines = "\n".allMatches(lastMatch[0]).toList();