output: drop stale references to wlr_output_attach_render()

It turns out we forgot about the function declaration in the header.
Also some docs were still referring to that function.

Move the wlr_output_attach_render() docs to
wlr_output_begin_render_pass().

include/types/wlr_output.h

@@ -12,7 +12,6 @@ bool output_pending_enabled(struct wlr_output *output,
 bool output_pick_format(struct wlr_output *output,
 	const struct wlr_drm_format_set *display_formats,
 	struct wlr_drm_format *format, uint32_t fmt);
-void output_clear_back_buffer(struct wlr_output *output);
 bool output_ensure_buffer(struct wlr_output *output,
 	struct wlr_output_state *state, bool *new_back_buffer);
 

include/wlr/types/wlr_output.h

@@ -283,7 +283,7 @@ void wlr_output_destroy_global(struct wlr_output *output);
  * renderer. After initialization, this function may invoked again to reinitialize
  * the allocator and renderer to different values.
  *
- * Call this function prior to any call to wlr_output_attach_render(),
+ * Call this function prior to any call to wlr_output_begin_render_pass(),
  * wlr_output_commit() or wlr_output_cursor_create().
  *
  * The buffer capabilities of the provided must match the capabilities of the
@@ -347,7 +347,7 @@ void wlr_output_enable_adaptive_sync(struct wlr_output *output, bool enabled);
  * hardware and software permit this.
  *
  * This only affects the format of the output buffer used when rendering,
- * as with wlr_output_attach_render(). It has no impact on the cursor buffer
+ * as with wlr_output_begin_render_pass(). It has no impact on the cursor buffer
  * format, or on the formats supported for direct scan-out (see also
  * wlr_output_attach_buffer()).
  *
@@ -391,19 +391,6 @@ void wlr_output_transformed_resolution(struct wlr_output *output,
  */
 void wlr_output_effective_resolution(struct wlr_output *output,
 	int *width, int *height);
-/**
- * Attach the renderer's buffer to the output. Compositors must call this
- * function before rendering. After they are done rendering, they should call
- * wlr_output_commit() to submit the new frame. The output needs to be
- * enabled.
- *
- * If non-NULL, `buffer_age` is set to the drawing buffer age in number of
- * frames or -1 if unknown. This is useful for damage tracking.
- *
- * If the compositor decides not to render after calling this function, it
- * must call wlr_output_rollback().
- */
-bool wlr_output_attach_render(struct wlr_output *output, int *buffer_age);
 /**
  * Attach a buffer to the output. Compositors should call wlr_output_commit()
  * to submit the new frame. The output needs to be enabled.
@@ -450,7 +437,7 @@ void wlr_output_set_layers(struct wlr_output *output,
  */
 bool wlr_output_test(struct wlr_output *output);
 /**
- * Commit the pending output state. If wlr_output_attach_render() has been
+ * Commit the pending output state. If wlr_output_begin_render_pass() has been
  * called, the pending frame will be submitted for display and a `frame` event
  * will be scheduled.
  *
@@ -721,7 +708,18 @@ bool wlr_output_configure_primary_swapchain(struct wlr_output *output,
 /**
  * Begin a render pass on this output.
  *
- * Same as wlr_output_attach_render(), but returns a struct wlr_render_pass.
+ * Compositors can call this function to begin rendering. After the render pass
+ * has been submitted, they should call wlr_output_commit_state() to submit the
+ * new frame.
+ *
+ * On error, NULL is returned. Creating a render pass on a disabled output is
+ * an error.
+ *
+ * The state describes the output changes the rendered frame will be
+ * committed with. A NULL state indicates no change.
+ *
+ * If non-NULL, buffer_age is set to the drawing buffer age in number of
+ * frames or -1 if unknown. This is useful for damage tracking.
  */
 struct wlr_render_pass *wlr_output_begin_render_pass(struct wlr_output *output,
 	struct wlr_output_state *state, int *buffer_age, struct wlr_render_timer *timer);