Fix docs mistake in bevy_ecs::world (#17336)

# Objective

- Correct a mistake in the rustdoc for bevy_ecs::world::World.

## Solution

- The rustdoc wrongly stated that "Each component can have up to one
instance of each component type.". This sentence should presumably be
"Each *Entity* can have up to one instance of each component type.".
Applying this change makes the prior sentence "Each [`Entity`] has a set
of components." redundant.

---------

Co-authored-by: François Mockers <[email protected]>

Author: berylllium

crates/bevy_ecs/src/world/mod.rs

@@ -70,9 +70,8 @@ use core::panic::Location;
 /// Stores and exposes operations on [entities](Entity), [components](Component), resources,
 /// and their associated metadata.
 ///
-/// Each [`Entity`] has a set of components. Each component can have up to one instance of each
-/// component type. Entity components can be created, updated, removed, and queried using a given
-/// [`World`].
+/// Each [`Entity`] has a set of unique components, based on their type.
+/// Entity components can be created, updated, removed, and queried using a given
 ///
 /// For complex access patterns involving [`SystemParam`](crate::system::SystemParam),
 /// consider using [`SystemState`](crate::system::SystemState).