docs: v.rectify.html fix typos (OSGeo#4619)

vector/v.rectify/v.rectify.html

@@ -177,11 +177,12 @@ <h3>Coordinate transformation and RMSE</h3>
 <p>The desired order of transformation (1, 2, or 3) is selected with the
 <b>order</b> option.
 
-<em>v.rectify</em> will calculate the RMSE if the <b>-r</b> flag is
-given and print out statistcs in tabular format. The last row gives a
-summary with the first column holding the number of active points,
-followed by average deviations for each dimension and both forward and
-backward transformation and finally forward and backward overall RMSE.
+If the <b>-r</b> flag is given, <em>v.rectify</em> will calculate the 
+Root Mean Square Error (RMSE) and print out statistics in tabular format.
+The last row gives a summary with the first column holding the number of 
+active points, followed by average deviations for each dimension and both 
+forward and backward transformation and finally forward and backward 
+overall RMSE.
 
 <h4>2D linear affine transformation (1st order transformation)</h4>