bsdconfig: Comments

My current style is to copy C for "/* NOTREACHED */" instead of spelling
out "Not reached". Make this one nominal change in this one file and the
others later.

While here, word-smith "Preload" into "Pre-load" as I believe that to
be more grammatically correct in this instance.

Also while here, fix a comment capitalization error.

Lastly, bump copyright for above changes.

usr.sbin/bsdconfig/bsdconfig

@@ -1,7 +1,7 @@
 #!/bin/sh
 #-
 # Copyright (c) 2012 Ron McDowell
-# Copyright (c) 2012-2014 Devin Teske
+# Copyright (c) 2012-2021 Devin Teske
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -132,7 +132,7 @@ usage()
 	#
 	local x=$longest_cmd ncols=1
 	x=$(( $x + 8 )) # Accommodate leading tab character
-	x=$(( $x + 3 + $longest_cmd )) # Preload end of next column
+	x=$(( $x + 3 + $longest_cmd )) # Pre-load end of next column
 	while [ $x -lt $max_width ]; do
 		ncols=$(( $ncols + 1 ))
 		x=$(( $x + 3 + $longest_cmd ))
@@ -176,7 +176,7 @@ usage()
 	        "PROGRAM_NAME" "$pgm" \
 	        "COMMAND_LIST" "$cmd_list"
 
-	# Never reached
+	# NOTREACHED
 }
 
 # dialog_menu_main
@@ -365,7 +365,7 @@ if [ "$1" ]; then
 	#
 	case "$1" in -help|--help|-\?)
 		usage
-		# Not reached
+		# NOTREACHED
 	esac
 
 	#
@@ -375,16 +375,16 @@ if [ "$1" ]; then
 	if ! { indexfile=$( f_index_file "$1" ) &&
 	       cmd=$( f_index_menusel_command "$indexfile" "$1" )
 	}; then
-		# no matches, display usage (which shows valid keywords)
+		# No matches, display usage (which shows valid keywords)
 		f_err "%s: %s: $msg_not_found\n" "$pgm" "$1"
 		usage
-		# Not reached
+		# NOTREACHED
 	fi
 
 	f_dprintf "cmd=[%s] *=[%s]" "$cmd" "$*"
 	shift
 	exec $cmd ${USE_XDIALOG:+-X} "$@" || exit 1
-	# Not reached
+	# NOTREACHED
 fi
 
 #