listSymbols -- compact display of symbols and their values

i1 : x:=3; y:="hi there"; z:=2^30; f = x->x;

i5 : listSymbols { symbol x, symbol y }

o5 = symbol   class     value      location of symbol
     ------   -----     -----      ------------------   
     x      : ZZ     -- 3          currentString:1:1-1:2
     y      : String -- "hi there" currentString:1:7-1:8

i6 : listSymbols first localDictionaries()

o6 = symbol   class     value      location of symbol
     ------   -----     -----      ------------------     
     x      : ZZ     -- 3          currentString:1:1-1:2  
     y      : String -- "hi there" currentString:1:7-1:8  
     z      : ZZ     -- 1073741824 currentString:1:22-1:23