[blueblur] Add Lightfield size information to level troubleshooting

hedgedocs/guides/hedgehog-engine/blueblur/levels/troubleshooting.md

@@ -131,4 +131,7 @@ The game doesn't load certain Sonic animations to save memory if the gimmick in
     <Order>0</Order>
   </Node>  
 </Node>
-```
+```
+
+### Lightfield File Too Large
+Your game might crash randomly when booting your level if the level's lightfield (.lft) file is too large. Try reducing the sample count or the minimum cell radius in HedgeGI to reduce the lightfield's file size.