Ruby: Made true and false booleans (#2098)

This makes `true` and `false` `boolean` tokens. Previously they were tokenized as `keyword`.

components/prism-ruby.js

@@ -13,7 +13,7 @@
 				greedy: true
 			}
 		],
-		'keyword': /\b(?:alias|and|BEGIN|begin|break|case|class|def|define_method|defined|do|each|else|elsif|END|end|ensure|extend|false|for|if|in|include|module|new|next|nil|not|or|prepend|protected|private|public|raise|redo|require|rescue|retry|return|self|super|then|throw|true|undef|unless|until|when|while|yield)\b/
+		'keyword': /\b(?:alias|and|BEGIN|begin|break|case|class|def|define_method|defined|do|each|else|elsif|END|end|ensure|extend|for|if|in|include|module|new|next|nil|not|or|prepend|protected|private|public|raise|redo|require|rescue|retry|return|self|super|then|throw|undef|unless|until|when|while|yield)\b/
 	});
 
 	var interpolation = {

tests/languages/ruby/boolean_feature.test

@@ -0,0 +1,13 @@
+true
+false
+
+----------------------------------------------------
+
+[
+	["boolean", "true"],
+	["boolean", "false"]
+]
+
+----------------------------------------------------
+
+Checks for booleans.

tests/languages/ruby/keyword_feature.test

@@ -16,7 +16,6 @@ END
 end
 ensure
 extend
-false
 for
 if
 in
@@ -41,7 +40,6 @@ self
 super
 then
 throw
-true
 undef
 unless
 until
@@ -70,7 +68,6 @@ yield
 	["keyword", "end"],
 	["keyword", "ensure"],
 	["keyword", "extend"],
-	["keyword", "false"],
 	["keyword", "for"],
 	["keyword", "if"],
 	["keyword", "in"],
@@ -95,7 +92,6 @@ yield
 	["keyword", "super"],
 	["keyword", "then"],
 	["keyword", "throw"],
-	["keyword", "true"],
 	["keyword", "undef"],
 	["keyword", "unless"],
 	["keyword", "until"],