housekeeping: corresponding changes for swagger-api/swagger-editor#1935 (via #5170)

* `schema` -> `structural`

* drop strip-instance transformer

src/core/plugins/err/error-transformers/hook.js

@@ -1,12 +1,10 @@
 import reduce from "lodash/reduce"
 import * as NotOfType from "./transformers/not-of-type"
 import * as ParameterOneOf from "./transformers/parameter-oneof"
-import * as StripInstance from "./transformers/strip-instance"
 
 const errorTransformers = [
   NotOfType,
-  ParameterOneOf,
-  StripInstance
+  ParameterOneOf
 ]
 
 export default function transformErrors (errors, system) {

src/core/plugins/err/error-transformers/transformers/parameter-oneof.js

@@ -38,7 +38,7 @@ function createTailoredParameterError(err, jsSpec) {
       message,
       path: err.get("path") + ".in",
       type: "spec",
-      source: "schema",
+      source: "structural",
       level: "error"
     })
   }
@@ -49,7 +49,7 @@ function createTailoredParameterError(err, jsSpec) {
       message,
       path: err.get("path") + ".collectionFormat",
       type: "spec",
-      source: "schema",
+      source: "structural",
       level: "error"
     })
   }

src/core/plugins/err/error-transformers/transformers/strip-instance.js

@@ -1,14 +0,0 @@
-export function transform(errors) {
-  return errors
-    .map(err => {
-      if(err.get("type") === "schema") {
-        return err.set("message", removeSubstring(err.get("message"), "instance\\."))
-      } else {
-        return err
-      }
-    })
-}
-
-function removeSubstring(str, substr) {
-  return str.replace(new RegExp(substr, "g"), "")
-}