Update file extension in documentation

Author: grahambell

hdsIsOpen.c

@@ -17,7 +17,7 @@
 
 *  Arguments:
 *     file = const char * (Given)
-*        Container file name. Use DAT__FLEXT (".h5sdf") if no suffix specified.
+*        Container file name. Use DAT__FLEXT (".sdf") if no suffix specified.
 *     isopen = int * (Returned)
 *        Pointer to a flag that is returned non-zero if the supplied
 *        container file is already open within HDS V5.
@@ -36,7 +36,7 @@
 *     {enter_new_authors_here}
 
 *  Notes:
-*     - A file extension of DAT__FLEXT (".h5sdf") is the default.
+*     - A file extension of DAT__FLEXT (".sdf") is the default.
 
 *  History:
 *     2020-10-15 (DSB):

hdsNew.c

@@ -18,7 +18,7 @@
 
 *  Arguments:
 *     file = const char * (Given)
-*        Container file name. Use DAT__FLEXT (".h5sdf") if no suffix specified.
+*        Container file name. Use DAT__FLEXT (".sdf") if no suffix specified.
 *     name = const char * (Given)
 *        Name of the object in the container.
 *     type = const char * (Given)
@@ -51,7 +51,7 @@
 *     {enter_new_authors_here}
 
 *  Notes:
-*     - A file extension of DAT__FLEXT (".h5sdf") is the default.
+*     - A file extension of DAT__FLEXT (".sdf") is the default.
 *     - HDF5 file opened with mode H5F_ACC_TRUNC.
 *     - HDF5 does not know how to create arrays of structures. When the HDS layer is asked
 *     to create a structure array a group (in the HDF5 sense) is created of that name

hdsOpen.c

@@ -35,7 +35,7 @@
 *     {enter_new_authors_here}
 
 *  Notes:
-*     - A file extension of DAT__FLEXT (".h5sdf") is the default.
+*     - A file extension of DAT__FLEXT (".sdf") is the default.
 *     - There is no difference betwee UPDATE and WRITE mode in HDF5
 *     - If the top-level object is a structure array, loc will be
 *       associated with the complete array, not the first cell. Thus,