openapi: Add default values to the thing_mount_path parameters (#18935)

changelog/18935.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+openapi: Add default values to thing_mount_path parameters
+```

sdk/framework/openapi.go

@@ -910,6 +910,9 @@ func (d *OASDocument) CreateOperationIDs(context string) {
 				continue
 			}
 
+			// Discard "_mount_path" from any {thing_mount_path} parameters
+			path = strings.Replace(path, "_mount_path", "", 1)
+
 			// Space-split on non-words, title case everything, recombine
 			opID := nonWordRe.ReplaceAllString(strings.ToLower(path), " ")
 			opID = strings.Title(opID)

vault/logical_system.go

@@ -4606,9 +4606,10 @@ func (b *SystemBackend) pathInternalOpenAPI(ctx context.Context, req *logical.Re
 						Description: "Path that the backend was mounted at",
 						In:          "path",
 						Schema: &framework.OASSchema{
-							Type: "string",
+							Type:    "string",
+							Default: strings.TrimRight(mount, "/"),
 						},
-						Required: true,
+						Required: false,
 					})
 				}