docs: add tooltip and popover workaround

Closes #4535

Author: Foxandxss

Diff for: src/popover/docs/readme.md

@@ -35,3 +35,12 @@ The popover directives require the `$position` service.
 The popover directive also supports various default configurations through the
 $tooltipProvider. See the [tooltip](#tooltip) section for more information.
 
+**Known issues**
+
+For Safari 7+ support, if you want to use **focus** `popover-trigger`, you need to use an anchor tag with a tab index. For example:
+
+```
+<a tabindex="0" popover="Test" popover-trigger="focus" class="btn btn-default">
+  Click Me
+</a>
+```

Diff for: src/tooltip/docs/readme.md

@@ -66,3 +66,12 @@ methods are available:
   appendToBody: false
   </pre>
 
+**Known issues**
+
+For Safari 7+ support, if you want to use the **focus** `tooltip-trigger`, you need to use an anchor tag with a tab index. For example:
+
+```
+<a tabindex="0" tooltip="Test" tooltip-trigger="focus" class="btn btn-default">
+  Click Me
+</a>
+```