fixes #892: oas 3.0 doesn't mention slashes not allowed

Author: Phil Sturgeon

versions/3.1.0.md

@@ -75,6 +75,8 @@ Path templating refers to the usage of template expressions, delimited by curly
 
 Each template expression in the path MUST correspond to a path parameter that is included in the [Path Item](#path-item-object) itself and/or in each of the Path Item's [Operations](#operation-object).
 
+The value for these path parameters MUST NOT contain unescaped forward slashes (`/`).
+
 ##### <a name="mediaTypes"></a>Media Types
 Media type definitions are spread across several resources.
 The media type definitions SHOULD be in compliance with [RFC6838](https://tools.ietf.org/html/rfc6838).
@@ -658,7 +660,7 @@ components:
 #### <a name="pathsObject"></a>Paths Object
 
 Holds the relative paths to the individual endpoints and their operations.
-The path is appended to the URL from the [`Server Object`](#serverObject) in order to construct the full URL.  The Paths MAY be empty, due to [Access Control List (ACL) constraints](#securityFiltering). Paths MAY be omitted in some classes of OAS documents, including referenced sub-documents and overlays.
+The path is appended to the URL from the [`Server Object`](#serverObject) in order to construct the full URL. The Paths MAY be empty, due to [Access Control List (ACL) constraints](#securityFiltering). Paths MAY be omitted in some classes of OAS documents, including referenced sub-documents and overlays.
 
 ##### Patterned Fields