[intro.execution] Clarify full-expression in example.

Fixes #1706.

Author: jensmaurer

source/basic.tex

@@ -4257,9 +4257,9 @@
   int I;
 };
 
-S s1(1);                   // full-expression is call of \tcode{S::S(int)}
+S s1(1);                   // full-expression comprises call of \tcode{S::S(int)}
 void f() {
-  S s2 = 2;                // full-expression is call of \tcode{S::S(int)}
+  S s2 = 2;                // full-expression comprises call of \tcode{S::S(int)}
   if (S(3).v())            // full-expression includes lvalue-to-rvalue and
                            // \tcode{int} to \tcode{bool} conversions, performed before
                            // temporary is deleted at end of full-expression