Flow: Recognise [Ss]ymbol as a type (#3388)

Author: hoonweiting

components/prism-flow.js

@@ -4,7 +4,7 @@
 	Prism.languages.insertBefore('flow', 'keyword', {
 		'type': [
 			{
-				pattern: /\b(?:[Bb]oolean|Function|[Nn]umber|[Ss]tring|any|mixed|null|void)\b/,
+				pattern: /\b(?:[Bb]oolean|Function|[Nn]umber|[Ss]tring|[Ss]ymbol|any|mixed|null|void)\b/,
 				alias: 'tag'
 			}
 		]

components/prism-flow.min.js

@@ -4,6 +4,8 @@ String
 string
 Boolean
 boolean
+Symbol
+symbol
 Function
 any
 mixed
@@ -19,6 +21,8 @@ void
 	["type", "string"],
 	["type", "Boolean"],
 	["type", "boolean"],
+	["type", "Symbol"],
+	["type", "symbol"],
 	["type", "Function"],
 	["type", "any"],
 	["type", "mixed"],
@@ -28,4 +32,4 @@ void
 
 ----------------------------------------------------
 
-Checks for types.
+Checks for types.