Remove deprecated _source_exclude and _source_include from get API spec (#42188)

Support for these parameters was removed in #35097. The spec were left outdated.

Author: delvedor

rest-api-spec/src/main/resources/rest-api-spec/api/get.json

@@ -58,14 +58,6 @@
           "type" : "list",
           "description" : "A list of fields to extract and return from the _source field"
         },
-        "_source_exclude": {
-          "type" : "list",
-          "description" : "A list of fields to exclude from the returned _source field"
-        },
-        "_source_include": {
-          "type" : "list",
-          "description" : "A list of fields to extract and return from the _source field"
-        },
         "version" : {
           "type" : "number",
           "description" : "Explicit version number for concurrency control"