Fix typo

src/vector/index.ts

@@ -27,7 +27,7 @@ require('katex/dist/katex.css');
 
 /**
  * This require is necessary only for purposes of CSS hot-reload, as otherwise
- * webpack has some incredibly problems figuring out which css files should be
+ * webpack has some incredible problems figuring out which CSS files should be
  * hot-reloaded, even with proper hints for the loader.
  *
  * On production build it's going to be an empty module, so don't worry about that.