docs: Fix typo (#10811)

Remove an extra word on https://www.chartjs.org/docs/latest/developers/publishing.html

Author: typpo

docs/developers/publishing.md

@@ -1,6 +1,6 @@
 # Publishing an extension
 
-If you are planning on publishing an extension for Chart.js, here are a some pointers.
+If you are planning on publishing an extension for Chart.js, here are some pointers.
 
 ## Awesome