File manager improvements (#936)

* add separate button for "save & close"

* make language selection for editor work

* fix download url

* add info banner for .pelicanignore files

* small cleanup

* fix import

* Move File Lang

* add `ctrl+shift+s` for save & close

* fix keybind

* cleanup and fix default value for edit

* remove unnecessary File::get & trait

* More EditorLanguages not matching their names

* mdx has its own highlighter

---------

Co-authored-by: notCharles <charles@pelican.dev>
Co-authored-by: RMartinOscar <40749467+RMartinOscar@users.noreply.github.com>

config/filament-monaco-editor.php

@@ -6,7 +6,7 @@ return [
         'show-full-screen-toggle' => true,
         'show-placeholder' => true,
         'placeholder-text' => 'Your code here...',
-        'show-loader' => true,
+        'show-loader' => false,
         'font-size' => '16px',
         'line-numbers-min-chars' => true,
         'automatic-layout' => true,