Enforce and fix comment_references lint (#138)

diff --git a/analysis_options.yaml b/analysis_options.yaml
index 090b8b2..53b584d 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -9,6 +9,7 @@
     - await_only_futures
     - camel_case_types
     - cancel_subscriptions
+    - comment_references
     - constant_identifier_names
     - control_flow_in_finally
     - directives_ordering
diff --git a/lib/src/arg_parser.dart b/lib/src/arg_parser.dart
index 72211ba..2ec5f62 100644
--- a/lib/src/arg_parser.dart
+++ b/lib/src/arg_parser.dart
@@ -113,7 +113,7 @@
   /// The [callback] argument is invoked with the flag's value when the flag
   /// is parsed. Note that this makes argument parsing order-dependent in ways
   /// that are often surprising, and its use is discouraged in favor of reading
-  /// values from the [ArgResult].
+  /// values from the [ArgResults].
   ///
   /// If [hide] is `true`, this option won't be included in [usage].
   ///
@@ -170,7 +170,7 @@
   /// The [callback] argument is invoked with the option's value when the option
   /// is parsed. Note that this makes argument parsing order-dependent in ways
   /// that are often surprising, and its use is discouraged in favor of reading
-  /// values from the [ArgResult].
+  /// values from the [ArgResults].
   ///
   /// The [allowMultiple] and [splitCommas] options are deprecated; the
   /// [addMultiOption] method should be used instead.
@@ -240,7 +240,7 @@
   /// The [callback] argument is invoked with the option's value when the option
   /// is parsed. Note that this makes argument parsing order-dependent in ways
   /// that are often surprising, and its use is discouraged in favor of reading
-  /// values from the [ArgResult].
+  /// values from the [ArgResults].
   ///
   /// If [splitCommas] is `true` (the default), multiple options may be passed
   /// by writing `--option a,b` in addition to `--option a --option b`.