console: loglevel: improve help text

I was confused about why setting the level to something lower didn't
seem to work, so this attempts make it more clear that not all log
levels are actually available on release builds.

Fixes #155

src/tangara/dev_console/console.cpp

@@ -73,7 +73,8 @@ void RegisterLogLevel() {
       .command = "loglevel",
       .help =
           "Sets the log level to one of \"VERBOSE\", \"DEBUG\", \"INFO\", "
-          "\"WARN\", \"ERROR\", \"NONE\"",
+          "\"WARN\", \"ERROR\", \"NONE\". NOTE: Some log levels aren't available "
+          "on release builds.",
       .hint = "level",
       .func = &CmdLogLevel,
       .argtable = NULL};