Adds _ and ~ as allowed slug characters

closes #636

app/utils/routeHelpers.js

@@ -66,7 +66,7 @@ export function notFoundUrl(): string {
 }
 
 export const matchDocumentSlug =
-  ':documentSlug([0-9a-zA-Z-]*-[a-zA-z0-9]{10,15})';
+  ':documentSlug([0-9a-zA-Z-_~]*-[a-zA-z0-9]{10,15})';
 
 export const matchDocumentEdit = `/doc/${matchDocumentSlug}/edit`;
 export const matchDocumentMove = `/doc/${matchDocumentSlug}/move`;