message: handle template tags
diff: @@ -53,10 +53,10 @@ function genSSRElement (el: ASTElement, state: CodegenState): string {
  return genFor(el, state, genSSRElement)
  } else if (el.if && !el.ifProcessed) {
  return genIf(el, state, genSSRElement)
  + } else if (el.tag === 'template' && !el.slotTarget) {
  + return genSSRChildren(el, state) || 'void 0'
  }
  - // TODO handle <template> tag
  - // TODO optimize style/class rendering
  // TODO optimize merge sibling nodes
  switch (el.ssrOptimizability) {
  @@ -137,6 +137,8 @@ function elementToSegments (el, state): Array<StringSegment> {
  type: EXPRESSION,
  value: genIf(el, state, elementToString, '""')
  }]
  + } else if (el.tag === 'template') {
  + return childrenToSegments(el, state)
  }
  const openSegments = elementToOpenTagSegments(el, state)
  