change REFERENCE to REFERENCES in the manual pages (thanks to Ludmila Furtkevicova)

       (merge https://trac.osgeo.org/grass/changeset/65678 from trunk)


git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@65679 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.param.scale/r.param.scale.html

@@ -87,7 +87,7 @@ r.param.scale in=elevation.10m output=morphology param=feature size=9
 Fix bug when `constrain through central cell' option selected. Create color
 tables for all output files (presently only on features).
 
-<h2>REFERENCE</h2>
+<h2>REFERENCES</h2>
 
 Wood, J. (1996): The Geomorphological characterisation of Digital Elevation
 Models. Diss., Department of Geography, University of Leicester, U.K.

raster/r.surf.fractal/r.surf.fractal.html

@@ -84,7 +84,7 @@ top: fractal dimension d=2.90 (left: elevation map, right: aspect map)
 </center>
 
 
-<h2>REFERENCE</h2>
+<h2>REFERENCES</h2>
 
 Saupe, D. (1988) Algorithms for random fractals, in Barnsley M., 
  Devaney R., Mandelbrot B., Peitgen, H-O., Saupe D., and Voss R.

scripts/d.polar/d.polar.html

@@ -59,7 +59,7 @@ d.polar aspect
 <a href="http://www.xgraph.org">Xgraph</a> must be installed for the
 <b>-x</b> flag to function.
 
-<h2>REFERENCE</h2>
+<h2>REFERENCES</h2>
 
 J. Hofierka, H. Mitasova, and M. Neteler (2009): Terrain parameterization in GRASS.
 In T. Hengl and H.I. Reuter, editors, Geomorphometry: concepts, software, applications. Elsevier

scripts/i.oif/i.oif.html

@@ -59,7 +59,7 @@ i.oif input=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_5
 </pre></div>
 
 
-<h2>REFERENCE</h2>
+<h2>REFERENCES</h2>
 
 Jensen, 1996. Introductory digital image processing. Prentice Hall, 
 p.98. ISBN 0-13-205840-5

vector/v.buffer/v.buffer.html

@@ -80,7 +80,7 @@ Buffer of 100m around the "lakes" polygons (map subset, original areas
 shown in black)
 </center>
 
-<h2>REFERENCE</h2>
+<h2>REFERENCES</h2>
 
 <ul>
 <li><a href="http://trac.osgeo.org/geos">GEOS Library</a></li>