deprecate ncplane_new()

include/notcurses/notcurses.h

@@ -1047,9 +1047,10 @@ typedef struct ncplane_options {
 // retrieved (and reset) later. A 'name' can be set, used in debugging.
 API struct ncplane* ncplane_create(struct ncplane* n, const ncplane_options* nopts);
 
-// This function will be marked deprecated in 2.0 in favor of ncplane_create().
-// It persists only for backwards compatibility.
-API struct ncplane* ncplane_new(struct ncplane* n, int rows, int cols, int y, int x, void* opaque, const char* name);
+// This function will be removed in 3.0 in favor of ncplane_create().
+// It persists in 2.0 only for backwards compatibility.
+API struct ncplane* ncplane_new(struct ncplane* n, int rows, int cols, int y, int x, void* opaque, const char* name)
+  __attribute__ ((deprecated));
 
 // Suitable for use as a `resizecb`. This will realign the plane 'n' against its
 // parent, using the alignment specified at ncplane_create()-time.