Fix typo: $schema to $schemas

Author: tom-tan

Process.yml

@@ -276,8 +276,8 @@ $graph:
         `<B> owl:equivalentClass <C>` and `<B> owl:subclassOf <A>` then infer
         `<C> owl:subclassOf <A>`.
 
-        File format ontologies may be provided in the "$schema" metadata at the
-        root of the document.  If no ontologies are specified in `$schema`, the
+        File format ontologies may be provided in the "$schemas" metadata at the
+        root of the document.  If no ontologies are specified in `$schemas`, the
         runtime may perform exact file format matches.
     - name: contents
       type: string?

concepts.md

@@ -319,7 +319,7 @@ prefix listed in the `$namespaces` section of the document as described in the
 [Schema Salad specification](SchemaSalad.html#Explicit_context).
 
 It is recommended that concepts from schema.org are used whenever possible.
-For the `$schema` field we recommend their RDF encoding: http://schema.org/version/latest/schema.rdf
+For the `$schemas` field we recommend their RDF encoding: http://schema.org/version/latest/schema.rdf
 
 Implementation extensions which modify execution semantics must be [listed in
 the `requirements` field](#Requirements_and_hints).