Rust: Improved punctuation and operators (#1839)

This improves Rust's existing punctuation and operators, adds support for new ones, and updates the tests.

components/prism-rust.js

@@ -63,6 +63,6 @@ Prism.languages.rust = {
 			'operator': /[&*]/
 		}
 	},
-	'punctuation': /[{}[\];(),:]|\.+|->/,
-	'operator': /[-+*\/%!^]=?|=[=>]?|@|&[&=]?|\|[|=]?|<<?=?|>>?=?/
-};
+	'punctuation': /->|\.\.=|\.{1,3}|::|[{}[\];(),:]/,
+	'operator': /[-+*\/%!^]=?|=[=>]?|&[&=]?|\|[|=]?|<<?=?|>>?=?|[@?]/
+};

tests/languages/rust/operator_feature.test

@@ -10,7 +10,7 @@
 | || |=
 < << <= <<=
 > >> >= >>=
-@
+@ ?
 
 ----------------------------------------------------
 
@@ -27,9 +27,9 @@
 	["operator", "|"], ["operator", "||"], ["operator", "|="],
 	["operator", "<"], ["operator", "<<"], ["operator", "<="], ["operator", "<<="],
 	["operator", ">"], ["operator", ">>"], ["operator", ">="], ["operator", ">>="],
-	["operator", "@"]
+	["operator", "@"], ["operator", "?"]
 ]
 
 ----------------------------------------------------
 
-Checks for all operators.
+Checks for all operators.

tests/languages/rust/punctuation_feature.test

@@ -0,0 +1,29 @@
+->
+. .. ... ..=
+::
+{} [] ()
+; , :
+
+----------------------------------------------------
+
+[
+	["punctuation", "->"],
+	["punctuation", "."],
+	["punctuation", ".."],
+	["punctuation", "..."],
+	["punctuation", "..="],
+	["punctuation", "::"],
+	["punctuation", "{"],
+	["punctuation", "}"],
+	["punctuation", "["],
+	["punctuation", "]"],
+	["punctuation", "("],
+	["punctuation", ")"],
+	["punctuation", ";"],
+	["punctuation", ","],
+	["punctuation", ":"]
+]
+
+----------------------------------------------------
+
+Checks for all punctuation.