Julia: Highlight ‘Inf’ and ‘NaN’ as constants (#1921)

This highlight `Inf`, `NaN` and all of their variants as constants.

components/prism-julia.js

@@ -8,5 +8,6 @@ Prism.languages.julia= {
 	'boolean' : /\b(?:true|false)\b/,
 	'number' : /(?:\b(?=\d)|\B(?=\.))(?:0[box])?(?:[\da-f]+\.?\d*|\.\d+)(?:[efp][+-]?\d+)?j?/i,
 	'operator': /[-+*^%÷&$\\]=?|\/[\/=]?|!=?=?|\|[=>]?|<(?:<=?|[=:])?|>(?:=|>>?=?)?|==?=?|[~≠≤≥]/,
-	'punctuation' : /[{}[\];(),.:]/
+	'punctuation' : /[{}[\];(),.:]/,
+	'constant': /\b(?:(?:NaN|Inf)(?:16|32|64)?)\b/
 };

tests/languages/julia/constant_feature.test

@@ -0,0 +1,19 @@
+NaN NaN16 NaN32 NaN64
+Inf Inf16 Inf32 Inf64
+
+----------------------------------------------------
+
+[
+	["constant", "NaN"],
+	["constant", "NaN16"],
+	["constant", "NaN32"],
+	["constant", "NaN64"],
+	["constant", "Inf"],
+	["constant", "Inf16"],
+	["constant", "Inf32"],
+	["constant", "Inf64"]
+]
+
+----------------------------------------------------
+
+Checks for all constants.