* refactor(sidebar-item): optimizate SiderbarItem. * chore: update nested examples. * fix: fix a wrong path. * fix: fix a transition bug. * fix: fix a wrong path. * perf: using "router" mode of el-menu. * Revert "perf: using "router" mode of el-menu." This reverts commit cef02a30b02a31242521e9e678cfeaad6f09448c. * fix: complement i18n text.