Remove redundant rules (toml-lang#847)

toml.abnf

@@ -92,10 +92,8 @@ ml-basic-string = ml-basic-string-delim [ newline ] ml-basic-body
 ml-basic-string-delim = 3quotation-mark
 ml-basic-body = *mlb-content *( mlb-quotes 1*mlb-content ) [ mlb-quotes ]
 
-mlb-content = mlb-char / newline / mlb-escaped-nl
-mlb-char = mlb-unescaped / escaped
+mlb-content = basic-char / newline / mlb-escaped-nl
 mlb-quotes = 1*2quotation-mark
-mlb-unescaped = wschar / %x21 / %x23-5B / %x5D-7E / non-ascii
 mlb-escaped-nl = escape ws newline *( wschar / newline )
 
 ;; Literal String
@@ -113,8 +111,7 @@ ml-literal-string = ml-literal-string-delim [ newline ] ml-literal-body
 ml-literal-string-delim = 3apostrophe
 ml-literal-body = *mll-content *( mll-quotes 1*mll-content ) [ mll-quotes ]
 
-mll-content = mll-char / newline
-mll-char = %x09 / %x20-26 / %x28-7E / non-ascii
+mll-content = literal-char / newline
 mll-quotes = 1*2apostrophe
 
 ;; Integer