Add ValueError (#2357)

pwndbg/dbg/gdb.py

@@ -29,7 +29,7 @@ class GDBRegisters(pwndbg.dbg_mod.Registers):
     def by_name(self, name: str) -> pwndbg.dbg_mod.Value | None:
         try:
             return GDBValue(self.frame.inner.read_register(name))
-        except gdb.error:
+        except (gdb.error, ValueError):
             # GDB throws an exception if the name is unknown, we just return
             # None when that is the case.
             pass