Fix typo

Author: chvmvd

README.md

@@ -22,7 +22,7 @@ This site is built using [Docusaurus](https://docusaurus.io/), a modern static s
 npm ci
 ```
 
-To run formatter or linter before committing, run the script below. (You don't have to run these scripts.)
+To run a formatter or linter before committing, run the script below. (You don't have to run these scripts.)
 
 ```shell
 # Install Poetry