Restore line break after rule ID and unwrap

We put line breaks after our rule identifiers.  For new text, or text
that would have to be rewrapped, we unwrap the lines.  Let's do that
here.

Author: traviscross

src/names/preludes.md

@@ -79,11 +79,8 @@ alloc/test limitation.
 r[names.preludes.extern.no_std]
 ### The `no_std` attribute
 
-r[names.preludes.extern.no_std.intro] By default, the standard library is
-automatically included in the crate root module. The [`std`] crate is added to
-the root. Both [`core`] and [`std`] are added to the [extern prelude]. Standard
-library macros are imported via [use declarations] and are *not* part of the
-[`macro_use` prelude].
+r[names.preludes.extern.no_std.intro]
+By default, the standard library is automatically included in the crate root module. The [`std`] crate is added to the root. Both [`core`] and [`std`] are added to the [extern prelude]. Standard library macros are imported via [use declarations] and are *not* part of the [`macro_use` prelude].
 
 r[names.preludes.extern.no_std.allowed-positions]
 The *`no_std` [attribute]* may be applied at the crate level to prevent the