grammar

Signed-off-by: aevesdocker <allie.sadler@docker.com>

docs/bake-reference.md

@@ -1112,7 +1112,7 @@ You can assign a default value for a variable in the Bake file,
 or assign a `null` value to it. If you assign a `null` value,
 Buildx uses the default value from the Dockerfile instead.
 
-You can also add a description of the variables purpose with the `description` field. This attribute is useful when combined with the `docker buildx bake --list=variables` option, providing a more informative output when listing the available variables in a Bake file.
+You can also add a description of the variable's purpose with the `description` field. This attribute is useful when combined with the `docker buildx bake --list=variables` option, providing a more informative output when listing the available variables in a Bake file.
 
 You can override variable defaults set in the Bake file using environment variables.
 The following example sets the `TAG` variable to `dev`,