output: update docs to reflect reality
The docs were outdated and weren't matching what the DRM backend does
(the only implementor of wlr_output_export_dmabuf).
@@ -391,8 +391,7 @@ size_t wlr_output_get_gamma_size(struct wlr_output *output);
void wlr_output_set_gamma(struct wlr_output *output, size_t size,
const uint16_t *r, const uint16_t *g, const uint16_t *b);
/**
- * Exports the output's current back-buffer as a DMA-BUF (ie. the buffer that
- * will be displayed on next commit).
+ * Exports the last committed buffer as a DMA-BUF.
*
* The caller is responsible for cleaning up the DMA-BUF attributes.
*/
