Fix bug in source-maps parsing: parser failed when most information could be

pkg/source_maps/lib/source_maps.dart

 // Copyright (c) 2013, 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.
 
-/// Source maps library.
-///
-/// ## Installing ##
-///
-/// Use [pub][] to install this package. Add the following to your
-/// `pubspec.yaml` file.
-///
-///     dependencies:
-///       source_maps: any
-///
-/// Then run `pub install`.
-///
-/// For more information, see the
-/// [source_maps package on pub.dartlang.org][pkg].
-///
-/// ## Using ##
+/// Library to create and parse source maps.
 ///
 /// Create a source map using [SourceMapBuilder]. For example:
 ///     var json = (new SourceMapBuilder()
 ///         ..add(inputSpan1, outputSpan1)
 ///         ..add(inputSpan2, outputSpan2)
 ///         ..add(inputSpan3, outputSpan3)
 ///         .toJson(outputFile);
 ///
 /// Use the [Span] and [SourceFile] classes to specify span locations.
 ///
 /// Parse a source map using [parse], and call `spanFor` on the returned mapping
 /// object. For example:
 ///     var mapping = parse(json);
 ///     mapping.spanFor(outputSpan1.line, outputSpan1.column)
 ///
+/// ## Getting the code ##
+///
+/// This library is distributed as a [pub][] package. To install this package,
+/// add the following to your `pubspec.yaml` file:
+///
+///     dependencies:
+///       source_maps: any
+///
+/// After you run `pub install`, you should be able to access this library by
+/// importing `package:source_maps/source_maps.dart`.
+///
+/// For more information, see the
+/// [source_maps package on pub.dartlang.org][pkg].
+///
 /// [pub]: http://pub.dartlang.org
 /// [pkg]: http://pub.dartlang.org/packages/source_maps
 library source_maps;
 
 export "builder.dart";
 export "parser.dart";
 export "printer.dart";
 export "span.dart";