Bug 1619519: Fix compound word

No need for a new lang string as this
only affects English.

behatnotneeded

Change-Id: Ibdaa4d679205b96742a33bdeb7ceccec9b37a52d

htdocs/lang/en.utf8/admin.php

@@ -914,7 +914,7 @@ $string['institutionshortname'] = 'Institution short name';
 $string['institutionnamealreadytaken'] = 'This institution name is already taken.';
 $string['institutiondisplayname'] = 'Institution display name';
 $string['institutionexpiry'] = 'Institution expiry date';
-$string['institutionshortnamedescription'] = 'The shortname is generated automatically and cannot be changed.';
+$string['institutionshortnamedescription'] = 'The short name is generated automatically and cannot be changed.';
 $string['institutionexpirydescription'] = 'The date at which this institutions membership of %s will be suspended.';
 $string['institutionlanguage'] = 'Language';
 $string['institutionlanguagedescription'] = 'The default language for users in this institution.';