Use nullish coalescing operator

CHANGELOG.md

@@ -9,7 +9,6 @@
 	- Fix files without module declaration not getting added to our index
 	- Fix rename devouring Module prefixes
 
-
 ## 0.7.3
 
 - Fix a case of wrong highlighting 

client/src/elmPackage.ts

@@ -57,7 +57,7 @@ function getInstallPackageCommand(packageToInstall: string): string {
     "elmLS",
   );
   let t: string = config.get("elmPath") as string;
-  t = t || "elm";
+  t = t ?? "elm";
 
   return t + " install " + packageToInstall;
 }