Added alias notice in help text

src/bin/hexyl.rs

@@ -36,7 +36,8 @@ fn run() -> Result<(), AnyhowError> {
                 .value_name("N")
                 .help(
                     "Only read N bytes from the input. The N argument can also include a \
-                     unit with a decimal prefix (kB, MB, ..) or binary prefix (kiB, MiB, ..).\n\
+                     unit with a decimal prefix (kB, MB, ..) or binary prefix (kiB, MiB, ..). \
+                     The short option '-l' can be used as an alias.\n\
                      Examples: --length=64, --length=4KiB",
                 ),
         )