docs: add isFetched to useQuery (#1810)

Author: bjarkehs

docs/src/pages/reference/useQuery.md

@@ -11,6 +11,7 @@ const {
   errorUpdatedAt,
   failureCount,
   isError,
+  isFetched,
   isFetchedAfterMount,
   isFetching,
   isIdle,
@@ -201,6 +202,8 @@ const result = useQuery({
   - Will be `true` if the data shown is the placeholder data.
 - `isPreviousData: boolean`
   - Will be `true` when `keepPreviousData` is set and data from the previous query is returned.
+- `isFetched: boolean`
+  - Will be `true` if the query has been fetched.
 - `isFetchedAfterMount: boolean`
   - Will be `true` if the query has been fetched after the component mounted.
   - This property can be used to not show any previously cached data.