Review comments and lint fixup for modern Dart

Author: jcollins-g

lib/src/line_number_cache.dart

@@ -8,7 +8,7 @@ import 'dart:collection';
 import 'dart:io';
 
 import 'package:dartdoc/src/tuple.dart';
-import 'package:path/path.dart' as pathLib;
+import 'package:path/path.dart' as path;
 
 String _getNewlineChar(String contents) {
   if (contents.contains("\r\n")) {
@@ -44,7 +44,7 @@ class LineNumberCache {
       <String, SplayTreeMap<int, int>>{};
 
   Tuple2<int, int> lineAndColumn(String file, int offset) {
-    file = pathLib.canonicalize(file);
+    file = path.canonicalize(file);
     var lineMap = _lineNumbers.putIfAbsent(
         file, () => _createLineNumbersMap(File(file).readAsStringSync()));
     var lastKey = lineMap.lastKeyBefore(offset);

test/line_number_cache_test.dart

@@ -1,4 +1,4 @@
-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -7,9 +7,9 @@ library dartdoc.cache_test;
 import 'dart:io';
 
 import 'package:dartdoc/src/line_number_cache.dart';
-import 'package:path/path.dart' as pathLib;
-import 'package:test/test.dart';
 import 'package:dartdoc/src/tuple.dart';
+import 'package:path/path.dart' as path;
+import 'package:test/test.dart';
 
 void main() {
   group('Verify basic line cache behavior', () {
@@ -24,15 +24,15 @@ void main() {
     });
 
     test('validate empty file behavior', () {
-      File emptyFile = File(pathLib.join(_tempDir.path, 'empty_file'))
+      File emptyFile = File(path.join(_tempDir.path, 'empty_file'))
         ..writeAsStringSync('');
       LineNumberCache cache = LineNumberCache();
       expect(cache.lineAndColumn(emptyFile.path, 0), equals(Tuple2(1, 0)));
     });
 
     test('single line without newline', () {
       File singleLineWithoutNewline =
-          File(pathLib.join(_tempDir.path, 'single_line'))
+          File(path.join(_tempDir.path, 'single_line'))
             ..writeAsStringSync('a single line');
       LineNumberCache cache = LineNumberCache();
       expect(cache.lineAndColumn(singleLineWithoutNewline.path, 2),
@@ -42,7 +42,7 @@ void main() {
     });
 
     test('multiple line without trailing newline', () {
-      File multipleLine = File(pathLib.join(_tempDir.path, 'multiple_line'))
+      File multipleLine = File(path.join(_tempDir.path, 'multiple_line'))
         ..writeAsStringSync('This is the first line\nThis is the second line');
       LineNumberCache cache = LineNumberCache();
       expect(cache.lineAndColumn(multipleLine.path, 60), equals(Tuple2(2, 38)));
@@ -52,7 +52,7 @@ void main() {
     });
 
     test('multiple lines with trailing newline', () {
-      File multipleLine = File(pathLib.join(_tempDir.path, 'multiple_line'))
+      File multipleLine = File(path.join(_tempDir.path, 'multiple_line'))
         ..writeAsStringSync(
             'This is the first line\nThis is the second line\n');
       LineNumberCache cache = LineNumberCache();