Make field description(help block) html safe and can output html tags.

flask_admin/templates/bootstrap2/admin/lib.html

@@ -137,7 +137,7 @@
       {{ field(**kwargs)|safe }}
     </div>
     {% if field.description %}
-    <p class="help-block">{{ field.description }}</p>
+    <p class="help-block">{{ field.description|safe }}</p>
     {% endif %}
     {% if direct_error %}
       <ul class="input-errors">

flask_admin/templates/bootstrap3/admin/lib.html

@@ -129,7 +129,7 @@
       {% set _dummy = kwargs.setdefault('class', 'form-control') %}
       {{ field(**kwargs)|safe }}
       {% if field.description %}
-      <p class="help-block">{{ field.description }}</p>
+      <p class="help-block">{{ field.description|safe }}</p>
       {% endif %}
       {% if direct_error %}
         <ul class="help-block input-errors">