Add a tooltip to Add Designs button

ee/app/assets/javascripts/design_management/components/upload/button.vue

 <script>
-import { GlButton, GlLoadingIcon } from '@gitlab/ui';
+import { GlButton, GlLoadingIcon, GlTooltipDirective } from '@gitlab/ui';
 
 export default {
   components: {
     GlButton,
     GlLoadingIcon,
   },
+  directives: {
+    GlTooltip: GlTooltipDirective,
+  },
   props: {
     isSaving: {
       type: Boolean,
@@ -25,7 +28,17 @@ export default {
 
 <template>
   <div>
-    <gl-button :disabled="isSaving" variant="primary" @click="openFileUpload">
+    <gl-button
+      v-gl-tooltip.hover
+      :title="
+        s__(
+          'DesignManagement|Adding a design with the same filename replaces the file in a new version.',
+        )
+      "
+      :disabled="isSaving"
+      variant="primary"
+      @click="openFileUpload"
+    >
       {{ s__('DesignManagement|Add designs') }}
       <gl-loading-icon v-if="isSaving" inline class="ml-1" />
     </gl-button>

ee/changelogs/unreleased/12908-add-a-tooltip-to-add-designs-button-to-inform-users-of-image-rep.yml

+---
+title: Add a tooltip to Add Designs button
+merge_request: 15471
+author:
+type: feature

ee/spec/frontend/design_management/components/upload/__snapshots__/button_spec.js.snap

@@ -5,6 +5,8 @@ exports[`Design management upload button component renders inverted upload desig
   isinverted="true"
 >
   <glbutton-stub
+    data-original-title="Adding a design with the same filename replaces the file in a new version."
+    title=""
     variant="primary"
   >
     
@@ -26,7 +28,9 @@ exports[`Design management upload button component renders inverted upload desig
 exports[`Design management upload button component renders loading icon 1`] = `
 <div>
   <glbutton-stub
+    data-original-title="Adding a design with the same filename replaces the file in a new version."
     disabled="true"
+    title=""
     variant="primary"
   >
     
@@ -54,6 +58,8 @@ exports[`Design management upload button component renders loading icon 1`] = `
 exports[`Design management upload button component renders upload design button 1`] = `
 <div>
   <glbutton-stub
+    data-original-title="Adding a design with the same filename replaces the file in a new version."
+    title=""
     variant="primary"
   >
     

locale/gitlab.pot

@@ -4960,6 +4960,9 @@ msgstr ""
 msgid "DesignManagement|Add designs"
 msgstr ""
 
+msgid "DesignManagement|Adding a design with the same filename replaces the file in a new version."
+msgstr ""
+
 msgid "DesignManagement|An error occurred while loading designs. Please try again."
 msgstr ""