[dcl.fct] Integrate return type requirements from [expr.call] and simplify them (#4113)

There is a general prohibition against arrays of function type in [dcl.array].
There is no need to highlight some specific permitted types; it is sufficient
to state the general rule.

Author: languagelawyer

source/declarations.tex

@@ -3605,10 +3605,7 @@
 \pnum
 \indextext{function return type|see{return type}}%
 \indextext{return type}%
-Functions shall not have a return type of type array or function,
-although they may have a return type of type pointer or reference to such things.
-There shall be no arrays of functions, although there can be arrays of pointers
-to functions.
+The return type shall be a non-array object type, a reference type, or \cv{}~\tcode{void}.
 
 \pnum
 A volatile-qualified return type is deprecated;

source/expressions.tex

@@ -3045,7 +3045,6 @@
 statically chosen function (i.e., ignoring the \tcode{virtual} keyword),
 even if the type of the function actually called is different.
 \indextext{type!incomplete}%
-This return type shall be an object type, a reference type or \cv{}~\tcode{void}.
 If the \grammarterm{postfix-expression} names a pseudo-destructor
 (in which case the \grammarterm{postfix-expression}
 is a possibly-parenthesized class member access),