Remove "Module" from "Loadable Module" menu options (redundant).
Expanded help text for "Loadable Modules". Expanded help text for internal code prefix/suffixes and some other edits. Internal-code prefixes are now automaitcally removed from imported file areas, just like was already done for message areas, by the prep_code() function. Imported internal-code suffixes are converted to upper case. Updated indentation and brace style. Replaced special unprintable help text chars with ASCII equivalents (` and ~).