Fixup: simplify C reference

Co-authored-by: A. Jiang <de34@live.cn>

Author: eisenwave

source/basic.tex

@@ -5847,9 +5847,7 @@
 should be chosen to increase compatibility and interoperability
 with the interchange floating types
 \tcode{_Float16}, \tcode{_Float32}, \tcode{_Float64}, and \tcode{_Float128}
-defined in \IsoC{}.
-
-\xrefc{H.2.2}
+defined in \IsoC{} H.2.2.
 
 \rSec2[basic.compound]{Compound types}