v.build.polylines.html: fix odd typo

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@58977 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.build.polylines/v.build.polylines.html

@@ -32,7 +32,7 @@ polylines.
 
 <h2>NOTES</h2>
 
-<em>v.build.polylines</em> combines only lines oif the same type to
+<em>v.build.polylines</em> combines only lines of the same type to
 a new polyline, i.e. lines and boundaries are kept separate.
 
 <p>Category number(s) are assigned to a polyline based on <b>cats</b> parameter.