Fixup: concepts validate *arguments*, not parameters

Author: CaseyCarter

source/lib-intro.tex

@@ -46,7 +46,7 @@
 
 \pnum
 The concepts library\iref{concepts.lib} describes library components that \Cpp{}
-programs may use to perform compile-time validation of template parameters and
+programs may use to perform compile-time validation of template arguments and
 perform function dispatch based on properties of types.
 
 \pnum