Add link to Sphinx-Design gutters

Author: agriyakhetarpal

layouts/shortcodes/grid.html

@@ -118,7 +118,8 @@
 
 {{< /grid >}}
 
-Here's a grid with gutters. A single value applies to all breakpoints.
+Here's a grid with [gutters](https://sphinx-design.readthedocs.io/en/pydata-theme/grids.html#controlling-spacing-between-items).
+A single value applies to all breakpoints.
 
 {{< grid columns="1 2 3 4" gutter="1" >}}