docs: improve docs and update api

one/docs/demo/table/tooltip.vue

@@ -0,0 +1,64 @@
+<template>
+<article>
+  <veui-table
+    :data="data"
+    key-field="id"
+  >
+    <veui-table-column
+      field="id"
+      title="ID"
+    />
+    <veui-table-column
+      field="name"
+      title="Name"
+    />
+    <veui-table-column
+      field="desc"
+      title="Description"
+      tooltip
+    />
+  </veui-table>
+</article>
+</template>
+
+<script>
+import { Table, Column } from 'veui'
+
+const long = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit. Quos, quibusdam! Pariatur, laboriosam? Voluptatibus, sunt.'
+const short = 'Lorem ipsum.'
+
+export default {
+  components: {
+    'veui-table': Table,
+    'veui-table-column': Column
+  },
+  data () {
+    return {
+      density: 'normal',
+      size: 'm',
+      data: [
+        {
+          id: '3154',
+          name: 'Steve Rogers',
+          desc: long
+        },
+        {
+          id: '3155',
+          name: 'Thor Odinson',
+          desc: short
+        },
+        {
+          id: '3156',
+          name: 'Tony Stark',
+          desc: short
+        },
+        {
+          id: '3157',
+          name: 'Stephen Strange',
+          desc: long
+        }
+      ]
+    }
+  }
+}
+</script>