Wrap and reword no_implicit_prelude code comments

One of the comments in the example stretched out a bit far; let's wrap
that and reword the comments in the example for clarity and flow.

Author: traviscross

src/names/preludes.md

@@ -160,10 +160,12 @@ The *`no_implicit_prelude` [attribute]* is used to prevent implicit preludes fro
 
 > [!EXAMPLE]
 > ```rust
-> // It can be applied to the crate root to apply to all modules.
+> // The attribute can be applied to the crate root to affect
+> // all modules.
 > #![no_implicit_prelude]
 >
-> // Or it can be applied to a module to only affect that module or any of its descendants.
+> // Or it can be applied to a module to only affect that module
+> // and its descendants.
 > #[no_implicit_prelude]
 > mod example {
 >     // ...