Add pre-commit check for the order of aspell dict

Suggested-by: Jim Huang <jserv@ccns.ncku.edu.tw>
Change-Id: Iff9a9eaed081f340ecbec758e741a3fb66863753

Author: lumynou5

Diff for: scripts/pre-commit.hook

@@ -222,6 +222,11 @@ if [ "${#SHELL_FILES[@]}" -gt 0 ]; then
   done
 fi
 
+ASPELL_DICT_FILE='scripts/aspell-pws'
+if ! tail -n +2 $ASPELL_DICT_FILE | sort -cdu; then
+  throw 'Aspell dictionary is unsorted or contains duplicated entries.'
+fi
+
 # Show insertion and deletion counts.
 if [ "${#FILES[@]}" -gt 0 ]; then
   echo "Following files were changed:"