Update CONTRIBUTING.md

fix my poor English

Author: vors

CONTRIBUTING.md

@@ -8,4 +8,4 @@ please, use it for pull requests.
 
 If you are fixing grammar (syntax highlighting), please, add affected samples to [test-file.ps1](/tests/samples/test-file.ps1). 
 We use it in automated tests that compare grammar against PowerShell tokenizer.
-It also serves as a place for humans to stair into all exotic language constructions.
+It also serves as a place for humans to stare to all exotic language constructions.