[class.spaceship] Remove vacuous conversion

The synthesized three-way comparison always produces a value of type R

Author: opensdh

source/classes.tex

@@ -6943,7 +6943,7 @@
 between $\tcode{x}_i$ and $\tcode{y}_i$
 yields a result value $\tcode{v}_i$ where $\tcode{v}_i \mathrel{\tcode{!=}} 0$,
 contextually converted to \tcode{bool}, yields \tcode{true};
-\tcode{V} is $\tcode{v}_i$ converted to \tcode{R}.
+\tcode{V} is $\tcode{v}_i$.
 If no such index exists, \tcode{V} is
 \tcode{std::strong_ordering::equal} converted to \tcode{R}.