revert "warn of SECURITY DEFINER schemas for non-sql_body funcs"

doc revert of commit 1703726.  Change was applied to irrelevant
branches, and was not detailed enough to be helpful in relevant
branches.

Reported-by: Peter Eisentraut, Noah Misch

Discussion: https://postgr.es/m/a2dc9de4-24fc-3222-87d3-0def8057d7d8@enterprisedb.com

Backpatch-through: 10

Author: bmomjian

doc/src/sgml/ref/create_function.sgml

@@ -779,10 +779,7 @@ SELECT * FROM dup(42);
    <para>
     Because a <literal>SECURITY DEFINER</literal> function is executed
     with the privileges of the user that owns it, care is needed to
-    ensure that the function cannot be misused.  This is particularly
-    important for non-<replaceable>sql_body</replaceable> functions because
-    their function bodies are evaluated at run-time, not creation time.
-    For security,
+    ensure that the function cannot be misused.  For security,
     <xref linkend="guc-search-path"/> should be set to exclude any schemas
     writable by untrusted users.  This prevents
     malicious users from creating objects (e.g., tables, functions, and