Merge pull request #9360 from nextcloud/backport/9357/stable25

[stable25] Document that the PHP extension `fileinfo` is required

admin_manual/installation/source_installation.rst

@@ -37,6 +37,7 @@ Required:
 * PHP module ctype
 * PHP module curl
 * PHP module dom
+* PHP module fileinfo (included with PHP)
 * PHP module filter (only on Mageia and FreeBSD)
 * PHP module GD
 * PHP module hash (only on FreeBSD)
@@ -60,7 +61,6 @@ Database connectors (pick the one for your database:)
 
 *Recommended* packages:
 
-* PHP module fileinfo (highly recommended, enhances file analysis performance; required to set custom theming images or if PHP module imagick with SVG support is installed)
 * PHP module bz2 (recommended, required for extraction of apps)
 * PHP module intl (increases language translation performance and fixes sorting
   of non-ASCII characters)