detect expressions ending with +0x<NUM>

In the examples that I tested, the mangled symbol ended with "+0x<NUMBER>", for example:
(_ZN7CxxTest14ErrorFormatter3runEv+0x18) [0xb1029a]

In the patch, I included the "+", so the expression above is also matched. The demangled output looks fine:
CxxTest::ErrorFormatter::run()+0x18

So far, I could not notice any negative side-effects.