iwyu: add a few dependencies to reduce white noise

entt.imp

@@ -39,4 +39,11 @@
   { "include": [ "@[\"<].*/signal/fwd\\.hpp[\">]", "private", "<entt/signal/dispatcher.hpp>", "public" ] },
   { "include": [ "@[\"<].*/signal/fwd\\.hpp[\">]", "private", "<entt/signal/emitter.hpp>", "public" ] },
   { "include": [ "@[\"<].*/signal/fwd\\.hpp[\">]", "private", "<entt/signal/sigh.hpp>", "public" ] }
+  # entity
+  { "include": [ "@[\"<].*/entity/sparse_set\\.hpp[\">]", "private", "<entt/entity/storage.hpp>", "public" ],
+  { "include": [ "@[\"<].*/entity/group\\.hpp[\">]", "private", "<entt/entity/registry.hpp>", "public" ],
+  { "include": [ "@[\"<].*/entity/mixin\\.hpp[\">]", "private", "<entt/entity/registry.hpp>", "public" ],
+  { "include": [ "@[\"<].*/entity/sparse_set\\.hpp[\">]", "private", "<entt/entity/registry.hpp>", "public" ],
+  { "include": [ "@[\"<].*/entity/storage\\.hpp[\">]", "private", "<entt/entity/registry.hpp>", "public" ],
+  { "include": [ "@[\"<].*/entity/view\\.hpp[\">]", "private", "<entt/entity/registry.hpp>", "public" ]
 ]