orthogonalSnGrad, uncorrectedSnGrad: Improved documentation

Resolves request http://bugs.openfoam.org/view.php?id=2364

src/finiteVolume/finiteVolume/snGradSchemes/orthogonalSnGrad/orthogonalSnGrad.H

@@ -25,7 +25,8 @@ Class
     Foam::fv::orthogonalSnGrad
 
 Description
-    Simple central-difference snGrad scheme without non-orthogonal correction.
+    Simple central-difference snGrad scheme using the cell-centre to cell-centre
+    delta-coefficients.
 
 SourceFiles
     orthogonalSnGrad.C

src/finiteVolume/finiteVolume/snGradSchemes/uncorrectedSnGrad/uncorrectedSnGrad.H

@@ -25,7 +25,8 @@ Class
     Foam::fv::uncorrectedSnGrad
 
 Description
-    Simple central-difference snGrad scheme without non-orthogonal correction.
+    Simple central-difference snGrad scheme using the non-orthogonal mesh
+    delta-coefficients but without non-orthogonal correction.
 
 SourceFiles
     uncorrectedSnGrad.C