[alg.rand.generate] Use \libconcept for sized_range (#6955)

Author: hewillk

source/algorithms.tex

@@ -11692,7 +11692,7 @@
 Calls \tcode{g.generate_random(std::forward<R>(r))}
 if this expression is well-formed.
 \item
-Otherwise, if \tcode{R} models \tcode{sized_range},
+Otherwise, if \tcode{R} models \libconcept{sized_range},
 fills \tcode{r} with \tcode{ranges::size(r)} values of
 type \tcode{invoke_result_t<G\&>} by performing
 an unspecified number of invocations of
@@ -11750,7 +11750,7 @@
 Calls \tcode{d.generate_random(std::forward<R>(r), g)}
 if this expression is well-formed.
 \item
-Otherwise, if \tcode{R} models \tcode{sized_range},
+Otherwise, if \tcode{R} models \libconcept{sized_range},
 fills \tcode{r} with \tcode{ranges::size(r)} values of
 type \tcode{invoke_result_t<D\&, G\&>}
 by performing an unspecified number of invocations of