document ebnflint

R=gri
http://go/go-review/1016034

src/cmd/ebnflint/doc.go

+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+
+The ebnflint program verifies that EBNF productions in an HTML document
+such as the Go specification document are consistent and grammatically correct.
+
+Grammar productions are grouped in boxes demarcated by the HTML elements
+	<pre class="ebnf">
+	</pre>
+
+
+Usage:
+	ebnflint [--start production] [file]
+
+The --start flag specifies the name of the start production for
+the grammar; it defaults to "Start".
+
+*/
+package documentation