[IMP] pos_order_return: improve description

pos_order_return/README.rst

@@ -42,7 +42,7 @@ A link is created between the returned Order Line and the initial Order Line.
 Configuration
 =============
 
-In some cases, you may want to let the possibility to allow negative quantity
+In some cases, you may want to block the possibility to allow negative quantity
 in a PoS Order, without mentioning initial order. This can happen for special
 products like returnable products, etc.
 

pos_order_return/readme/CONFIGURE.rst

@@ -1,4 +1,4 @@
-In some cases, you may want to let the possibility to allow negative quantity
+In some cases, you may want to block the possibility to allow negative quantity
 in a PoS Order, without mentioning initial order. This can happen for special
 products like returnable products, etc.
 

pos_order_return/static/description/index.html

@@ -392,7 +392,7 @@ A link is created between the returned Order Line and the initial Order Line.</p
 </div>
 <div class="section" id="configuration">
 <h1><a class="toc-backref" href="#id1">Configuration</a></h1>
-<p>In some cases, you may want to let the possibility to allow negative quantity
+<p>In some cases, you may want to block the possibility to allow negative quantity
 in a PoS Order, without mentioning initial order. This can happen for special
 products like returnable products, etc.</p>
 <p>In that case, a checkbox is possible on Product Form View to allow such case</p>