ENH: add bin/tool/find-trailingwhitespace

doc/tools/find-trailingspace

+#!/bin/bash
+# -----------------------------------------------------------------------------
+# Script
+#     find-trailingspace
+#
+# Description
+#     Search for files with trailing whitesapce
+#
+# -----------------------------------------------------------------------------
+set -x
+cd $WM_PROJECT_DIR || exit 1
+
+tab=$'\t'
+
+git grep -c -E "[ $tab]+"'$' -- $@
+
+#------------------------------------------------------------------ end-of-file