Fix error link (#15082)

# Objective

A previous issue describes the same problem: #14248.

This particular link was seemingly missed by #14276.

## Solution

- Search repo for `bevyengine.org/learn/errors/#`
- Remove `#`
- Verify link goes to right place

crates/bevy_ecs/src/system/commands/mod.rs

@@ -1049,7 +1049,7 @@ impl EntityCommands<'_> {
         let caller = Location::caller();
         // SAFETY: same invariants as parent call
         self.add(unsafe {insert_by_id(component_id, value, move |entity| {
-            panic!("error[B0003]: {caller}: Could not insert a component {component_id:?} (with type {}) for entity {entity:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/#b0003", std::any::type_name::<T>());
+            panic!("error[B0003]: {caller}: Could not insert a component {component_id:?} (with type {}) for entity {entity:?} because it doesn't exist in this World. See: https://bevyengine.org/learn/errors/b0003", std::any::type_name::<T>());
         })})
     }