<form {{on "submit" this.joinChannel}}>
  <div class="grid grid-cols-1 gap-2">
    <label for="channel-name" class="hidden">Channel</label>
    <div class="flex justify-center items-center">
      <Input name="channel-name" @type="text" @value={{this.channelName}}
             aria-label="channel name" placeholder="channel"
             required class="flex-grow min-w-0" {{autofocus}} />
      <span class="flex-0 mx-1 text-xl">@</span>
      <Input name="channel-domain" @type="text" @value={{this.channelDomain}}
             aria-label="domain" placeholder="domain"
             required class="flex-grow min-w-0" />
      <input type="submit" value="Join" aria-label="Join"
             class="flex-none ml-4 btn-md btn-blue" />
    </div>
  </div>
  <!-- TODO -->
  <!-- <div class="mt-6"> -->
  <!--   Advanced options -->
  <!-- </div> -->
  <!-- <div class="mt&#45;6 grid grid&#45;cols&#45;1 gap&#45;2 sm:grid&#45;cols&#45;10 sm:gap&#45;4 sm:items&#45;center"> -->
  <!--   <label for="nickname" class="sm:col&#45;span&#45;3 pr&#45;4">Nickname</label> -->
  <!--   <Input name="nickname" @type="text" @value={{this.nickname}} -->
  <!--          required class="sm:col&#45;span&#45;7" /> -->
  <!-- </div> -->
</form>

<form {{on "submit" this.joinChannel}}>
  <div class="grid grid-cols-1 gap-2">
    <label for="channel-name" class="hidden">Channel</label>
    <div class="flex justify-center items-center">
      <Input name="channel-name" @type="text" @value={{this.channelName}}
             aria-label="channel name" placeholder="channel"
             required class="flex-grow min-w-0" {{autofocus}} />
      <span class="flex-0 mx-1 text-xl">@</span>
      <Input name="channel-domain" @type="text" @value={{this.channelDomain}}
             aria-label="domain" placeholder="domain"
             required class="flex-grow min-w-0" />
      <input type="submit" value="Join" aria-label="Join"
             class="flex-none ml-4 btn-md btn-blue" />
    </div>
  </div>
  {{!--
  <!-- TODO -->
  <div class="mt-6">
    Advanced options
  </div>
  <div class="mt-6 grid grid-cols-1 gap-2 sm:grid-cols-10 sm:gap-4 sm:items-center">
    <label for="nickname" class="sm:col-span-3 pr-4">Nickname</label>
    <Input name="nickname" @type="text" @value={{this.nickname}}
           required class="sm:col-span-7" />
  </div>
  --}}
</form>

Use HBS comments instead of HTML comments
Use HBS comments instead of HTML comments

This fixes the linter errors
