sokol_gfx.h: fix validation message for VALIDATE_BUFFERDESC_SIZE

sokol_gfx.h

@@ -2649,7 +2649,7 @@ typedef struct sg_pass_info {
     _SG_LOGITEM_XMACRO(PASS_POOL_EXHAUSTED, "pass pool exhausted") \
     _SG_LOGITEM_XMACRO(DRAW_WITHOUT_BINDINGS, "attempting to draw without resource bindings") \
     _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_CANARY, "sg_buffer_desc not initialized") \
-    _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_SIZE, "sg_buffer_desc.size cannot be 0") \
+    _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_SIZE, "sg_buffer_desc.size and .data.size cannot both be 0") \
     _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_DATA, "immutable buffers must be initialized with data (sg_buffer_desc.data.ptr and sg_buffer_desc.data.size)") \
     _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_DATA_SIZE, "immutable buffer data size differs from buffer size") \
     _SG_LOGITEM_XMACRO(VALIDATE_BUFFERDESC_NO_DATA, "dynamic/stream usage buffers cannot be initialized with data") \