docs: add note

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/blas/ext/base/gfind-last-index/docs/types/index.d.ts

@@ -99,6 +99,8 @@ interface Routine {
 	*     -   `sidx`: strided index (offset + aidx*stride)
 	*     -   `array`: input array
 	*
+	* -   If no element passes a test implemented by a predicate function, the function returns `-1`.
+	*
 	* @param N - number of indexed elements
 	* @param x - input array
 	* @param strideX - stride length
@@ -130,6 +132,8 @@ interface Routine {
 	*     -   `sidx`: strided index (offset + aidx*stride)
 	*     -   `array`: input array
 	*
+	* -   If no element passes a test implemented by a predicate function, the function returns `-1`.
+	*
 	* @param N - number of indexed elements
 	* @param x - input array
 	* @param strideX - stride length
@@ -163,6 +167,8 @@ interface Routine {
 *     -   `sidx`: strided index (offset + aidx*stride)
 *     -   `array`: input array
 *
+* -   If no element passes a test implemented by a predicate function, the function returns `-1`.
+*
 * @param N - number of indexed elements
 * @param x - input array
 * @param strideX - stride length