[selectors] Remove the Selectors-specific tokens, rephrase in terms of delim tokens.

Author: tabatkins

selectors/Overview.bs

@@ -3152,7 +3152,7 @@ Grammar</h2>
 
 	<dfn>&lt;relative-selector></dfn> = <<combinator>>? <<complex-selector>>
 
-	<dfn>&lt;combinator></dfn> = '>>' | '>' | '+' | '~' | <<column-token>>
+	<dfn>&lt;combinator></dfn> = '>>' | '>' | '+' | '~' | [ '|' '|' ]
 
 	<dfn>&lt;compound-selector></dfn> = <<simple-selector>>+
 
@@ -3173,8 +3173,7 @@ Grammar</h2>
 	<dfn>&lt;attribute-selector></dfn> = '[' <<wq-name>> ']' |
 	                       '[' <<wq-name>> <<attr-matcher>> [ <<string-token>> | <<ident-token>> ] <<attr-modifier>>? ']'
 
-	<dfn>&lt;attr-matcher></dfn> = '=' | <<include-match-token>> | <<dash-match-token>> | <<prefix-match-token>> |
-	                 <<suffix-match-token>> | <<substring-match-token>>
+	<dfn>&lt;attr-matcher></dfn> = [ '~' | '|' | '^' | '$' | '*' ]? '='
 
 	<dfn>&lt;attr-modifier></dfn> = i