Update Single_crystal.comp

Author: tweber-ill

mcstas-comps/samples/Single_crystal.comp

@@ -17,6 +17,7 @@
 * Modified by: EF, PW, 2015: powder/PG and texture mode
 * Modified by: PW, May 2017: Remove statement about being under validation
 * Modified by: PW, June 2017: Doc updates
+* Modified by: T. Weber, October 2017: new focus code
 * Modified by: PW, Feb 2018:  GPU edits
 * Modified by: EF, June 2023: can now read CIF files
 * Modified by: MB, November 2024: Fixed issue with leaving crystal due to order