Correct javadoc

src/main/java/org/orekit/rugged/intersection/ConstantElevationAlgorithm.java

@@ -25,7 +25,7 @@ import org.orekit.rugged.utils.NormalizedGeodeticPoint;
 
 /** Intersection ignoring Digital Elevation Model.
  * <p>
- * This dummy implementation simply uses the ellipsoid itself.
+ * This implementation uses a constant elevation over the ellipsoid.
  * </p>
  * @author Luc Maisonobe
  */

src/main/java/org/orekit/rugged/raster/TileUpdater.java

@@ -18,7 +18,7 @@ package org.orekit.rugged.raster;
 
 /** Interface used to update Digital Elevation Model tiles.
  * <p>
- * Implementations of this interface are must be provided by
+ * Implementations of this interface must be provided by
  * the image processing mission-specific layer, thus allowing
  * the Rugged library to access the Digital Elevation Model data.
  * </p>