Correctly recognise "Syntax OK" message from dead_end

Current latest dead_end (v4.0.0) appends a newline to the "Syntax OK"
message. Presumably this was not the case with older versions which is
why this extension was not expecting the newline. This change updates
this extension to not care about the newline.

Author: eoinkelly

extension.js

@@ -19,8 +19,10 @@ function activate(context) {
           deadEndOutput = stderr;
         }
 
+        const syntaxOkOutputRegex = /Syntax OK\s*/;
         console.log(deadEndOutput);
-        if (deadEndOutput == "Syntax OK") return;
+
+        if (syntaxOkOutputRegex.test(deadEndOutput)) return;
 
         const lineRegex = /❯\s+(\d+)(.*)/g;
         const allLines = [];