Update schema.md

Update grammar

Author: arungurung

docs/concept/schema.md

@@ -25,7 +25,7 @@ The schema consists of:
 - params - validate path parameters.
 - header - validate request's headers.
 - response - validate response type.
-- detail - Explicitly define what can route does, see ([creating documentation](/patterns/creating-documentation)) for more explanation.
+- detail - Explicitly define what a route can do, see ([creating documentation](/patterns/creating-documentation)) for more explanation.
 
 Schema is defined as:
 - Locally: in a handler