Function clear

Libs/sol/sol.hpp:10632–10644

		}

		inline void clear(lua_State* L, int table_index) {
			lua_pushnil(L);
			while (lua_next(L, table_index) != 0) {
				// remove value
				lua_pop(L, 1);
				// duplicate key to protect form rawset
				lua_pushvalue(L, -1);
				// push new value
				lua_pushnil(L);
				// table_index%[key] = nil
				lua_rawset(L, table_index);
			}
		}

		inline void clear(reference& r) {
			auto pp = push_pop<false>(r);