message: [bugfix] Tag: white border
diff: <template>
  <span
  - class="van-hairline--surround"
  - :class="b({
  + :class="[b({
  mark,
  plain,
  [type]: type
  - })"
  + }), {
  + 'van-hairline--surround': plain
  + }]"
  >
  <slot />
  </span>
  