explanatory comment

git-svn-id: svn+ssh://svn.cprover.org/srv/svn/cbmc/trunk@3527 6afb6bc1-c8e4-404c-8f48-9ae832c5b171

src/analyses/locals.h

@@ -24,7 +24,10 @@ public:
   }
 
   void output(std::ostream &out) const;
-  
+
+  // returns true for all procedure-local variables,
+  // not including those with static storage duration,
+  // but including parameters.
   inline bool is_local(const irep_idt &identifier) const
   {
     return locals_map.find(identifier)!=locals_map.end();