[except.pre] Add \grammarterm for ctor-initializer in comment (#8726)

Author: Andreas-Krug

source/exceptions.tex

@@ -177,7 +177,7 @@
 try : i(f(ii)), d(id) {
     // constructor statements
 } catch (...) {
-    // handles exceptions thrown from the ctor-initializer and from the constructor statements
+    // handles exceptions thrown from the \grammarterm{ctor-initializer} and from the constructor statements
 }
 \end{codeblock}
 \end{example}