refactor(clean): removed useless br tags

src/tools/chronometer/chronometer.vue

@@ -3,8 +3,7 @@
     <n-card>
       <div class="duration">{{ formatMs(counter) }}</div>
     </n-card>
-    <br />
-    <n-space justify="center">
+    <n-space justify="center" mt-5>
       <c-button v-if="!isRunning" secondary type="primary" @click="resume">Start</c-button>
       <c-button v-else secondary type="warning" @click="pause">Stop</c-button>