FR: Support libraries with the `Import scripts` feature

References: * https://sourceforge.net/p/greasemonkey/wiki/Metadata_Block/ * https://openuserjs.org/about/Userscript-Beginners-HOWTO#what-is-a-library-script- --- There are at least two ways of identifying libraries: * The use of `==UserLibrary==` in the metadata block * File extension of `.js` and NOT `.user.js` It would be nice if, when using the import feature, either or both of those could be used to mark a new import as a library rather than a script. (and perhaps rejecting if there is a mismatch) --- I cannot recall where I read this, but one recommendation I saw (and one I use), is that the metadata block should look like the following for best compatibility between suppliers (GF, OUJS) and managers (GM, VM, TM, FM). ``` // ==UserScript== // ==UserLibrary== // @name Name // @description Base library usable any time. // @version 123 // @license GPL-3.0-or-later; https://www.gnu.org/licenses/gpl-3.0-standalone.html // @homepageURL https://github.com/octocat/userscripts // @supportURL https://github.com/octocat/userscripts/issues // @match https://www.example.com/* // ==/UserLibrary== // ==/UserScript== ``` (I forget which system actually requires the `@match`, but I want to say it was GF.)