Update instances.md grammar (#640)

Author: thecodingaviator

docs/instances.md

@@ -6,7 +6,7 @@
 
 **Warning: Any public instance that isn't in this list is considered untrustworthy. Use them at your own risk.**
 
-**The list of public instances is short due to the [recent YouTube issues](https://github.com/iv-org/invidious/issues/4734). If you can [please host Invidious at home](./installation.md) instead of using a public instance.**
+**The list of public instances is short due to the [recent YouTube issues](https://github.com/iv-org/invidious/issues/4734). If you can, [please host Invidious at home](./installation.md) instead of using a public instance.**
 
 ## List of public Invidious Instances (sorted from oldest to newest):