Update CONTRIBUTING.md

Update English convention

Author: grzegorzkrukowski

CONTRIBUTING.md

@@ -52,12 +52,12 @@ Images should go into dedicated `images` folder:
 
 ### English style convention
 
-Use American English spelling and style in your code and command metadata. 
+Use American English spelling and style for your command metadata. 
 To make sure you use the right version, refer to [Wikipedia](https://en.wikipedia.org/wiki/Comparison_of_American_and_British_English) or use [British to American English Converter](https://www.infoenglish.net/british-to-american-english/)
 
 ### File naming convention
 
-Use dash-case format for script files and directories, and use proper file extensions: Applescript should be `.applescript`, Swift should be `.swift`, Bash should be `.sh`, etc.
+Use lowercased, dash-case format for script files and directories, and use proper file extensions: Applescript should be `.applescript`, Swift should be `.swift`, Bash should be `.sh`, etc.
 Example: `spotify-next-track.applescript`
 
 ### Metadata convention