chore: revert status code change for delete users endpoint (#14168)

Revert from https://github.com/coder/coder/pull/13870

coderd/apidoc/docs.go

@@ -4935,8 +4935,8 @@ const docTemplate = `{
                     }
                 ],
                 "responses": {
-                    "204": {
-                        "description": "No Content"
+                    "200": {
+                        "description": "OK"
                     }
                 }
             }

coderd/apidoc/swagger.json

@@ -4351,8 +4351,8 @@
           }
         ],
         "responses": {
-          "204": {
-            "description": "No Content"
+          "200": {
+            "description": "OK"
           }
         }
       }

coderd/users.go

@@ -513,7 +513,7 @@ func (api *API) postUser(rw http.ResponseWriter, r *http.Request) {
 // @Security CoderSessionToken
 // @Tags Users
 // @Param user path string true "User ID, name, or me"
-// @Success 204
+// @Success 200
 // @Router /users/{user} [delete]
 func (api *API) deleteUser(rw http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
@@ -588,7 +588,9 @@ func (api *API) deleteUser(rw http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	rw.WriteHeader(http.StatusNoContent)
+	httpapi.Write(ctx, rw, http.StatusOK, codersdk.Response{
+		Message: "User has been deleted!",
+	})
 }
 
 // Returns the parameterized user requested. All validation