v.overlay manual cosmetics

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@54138 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.overlay/v.overlay.html

@@ -126,9 +126,10 @@ b_UA_TYPE|UA
 <i>v.overlay: Polygon union (right) of urban area (left) and Census 2000 (middle) areas (North Carolina dataset)</i>
 </center>
 
+<p>
 As can be seen by the resulting large number of centroids on boundaries, 
 the urban areas do not match exactly the Census 2000 areas. In this case 
-a clean result can be obtained by snapping with a threshold of 0.1 (1 cm).
+a clean result can be obtained by snapping with a threshold of 0.1 m.
 
 <h4>Lines overlaid with polygons</h4>