update title to match the TOC (dotnet#2667)

All headings indicate that this is a draft spec.

Author: BillWagner

docs/csharp/language-reference/language-specification/index.md

@@ -1,5 +1,5 @@
 ---
-title: "C# Language Specification | Microsoft Docs"
+title: "C# 6.0 draft Language Specification | Microsoft Docs"
 ms.date: "2017-07-01"
 ms.prod: .net
 ms.technology: 
@@ -31,7 +31,7 @@ translation.priority.ht:
   - "zh-cn"
   - "zh-tw"
 ---
-# C# Language Specification
+# C# 6.0 draft Language Specification
 The C# Language Specification is the definitive source for C# syntax and usage. This specification contains detailed information about all aspects of the language, including many points that the documentation for Visual C# doesn't cover.
 
 You can download version 5.0 of this specification from the [Microsoft Download Center](http://www.microsoft.com/download/details.aspx?id=7029). If you've installed Visual Studio 2015, you can also find the specification on your computer in the Program Files (x86)/Microsoft Visual Studio 14.0/VC#/Specifications/1033 folder. If you have another version of Visual Studio installed or if you installed Visual Studio in a language other than English, change the path as appropriate.

docs/csharp/language-reference/toc.md

@@ -6,4 +6,4 @@
 ## [C# Preprocessor Directives](preprocessor-directives/)
 ## [C# Compiler Options](compiler-options/)
 ## [C# Compiler Errors](compiler-messages/)
-## [C# Language Specification](language-specification/)
+## [C# 6.0 draft Language Specification](language-specification/)