UI: example should have a space after the icon

See civicrm/civicrm-core#18005 for work
to standardize this, but it's already common practice.

docs/framework/ui.md

@@ -184,7 +184,7 @@ For example, to insert a [bullhorn icon](http://fortawesome.github.io/Font-Aweso
 use the following:
 
 ```html
-<div><i class="crm-i fa-bullhorn" aria-hidden="true"></i>Create new announcement</div>
+<div><i class="crm-i fa-bullhorn" aria-hidden="true"></i> Create new announcement</div>
 ```
 
 See the [Screen reader text](#screen-reader-text) section below for including text necessary to convey information that icons otherwise indicate visually.  Not all icons need screen reader text, but an icon on its own might be visually efficient but require verbal explanation for visually-impaired users.