Remove unused permitFsharpKeywords switch

Author: forki

src/fsharp/CompileOptions.fs

@@ -891,7 +891,7 @@ let compilingFsLib20Flag (tcConfigB : TcConfigBuilder) =
 let compilingFsLib40Flag (tcConfigB : TcConfigBuilder) = 
         CompilerOption("compiling-fslib-40", tagNone, OptionUnit (fun () -> tcConfigB.compilingFslib40 <- true; ), Some(InternalCommandLineOption("--compiling-fslib-40", rangeCmdArgs)), None)
 let mlKeywordsFlag = 
-        CompilerOption("ml-keywords", tagNone, OptionUnit (fun () -> Lexhelp.Keywords.permitFsharpKeywords <- false), Some(DeprecatedCommandLineOptionNoDescription("--ml-keywords", rangeCmdArgs)), None)
+        CompilerOption("ml-keywords", tagNone, OptionUnit (fun () -> ()), Some(DeprecatedCommandLineOptionNoDescription("--ml-keywords", rangeCmdArgs)), None)
 
 let gnuStyleErrorsFlag tcConfigB = 
         CompilerOption("gnu-style-errors", tagNone, OptionUnit (fun () -> tcConfigB.errorStyle <- ErrorStyle.EmacsErrors), Some(DeprecatedCommandLineOptionNoDescription("--gnu-style-errors", rangeCmdArgs)), None)

src/fsharp/lexhelp.fsi

@@ -67,5 +67,4 @@ module Keywords =
     val KeywordOrIdentifierToken : lexargs -> UnicodeLexing.Lexbuf -> string -> Parser.token
     val IdentifierToken : lexargs -> UnicodeLexing.Lexbuf -> string -> Parser.token
     val QuoteIdentifierIfNeeded : string -> string
-    val mutable permitFsharpKeywords : bool 
     val keywordNames : string list