transformations: remove "auto-detect" MIME-type that was never implemented

ChangeLog

@@ -74,6 +74,7 @@ $HeadURL: https://phpmyadmin.svn.sourceforge.net/svnroot/phpmyadmin/trunk/phpMyA
 + RFE #1743983 [gui] Replace $max_characters by a configurable param:
   $cfg['MaxCharactersInDisplayedSQL']
 - bug #1746186 LeftLogoLink fails if set to some external site
+. [transformations]: remove "auto-detect" MIME-type that was never implemented
 
 2.10.3.0 (not yet released)
 

Documentation.html

@@ -2106,8 +2106,8 @@ $cfg['TrustedProxies'] =
     the end of the line. They are called 'MIME-type', 'Browser transformation' and
     'Transformation options'.</p>
 
-<ul><li>The field 'MIME-type' is a dropdown field. You have the options to leave that field
-        empty or to use 'auto' [this feature is not yet available]. Please note that
+    <ul><li>The field 'MIME-type' is a drop-down field. Select the MIME-type
+	that corresponds to the column's contents. Please note that
         transformations are inactive as long as no MIME-type is selected.</li>
 
     <li>The field 'Browser transformation' is a drop-down field. You can choose from a

libraries/tbl_properties.inc.php

@@ -528,7 +528,6 @@ for ($i = 0 ; $i <= $num_fields; $i++) {
     if ($cfgRelation['mimework'] && $cfg['BrowseMIME'] && $cfgRelation['commwork']) {
         $content_cells[$i][$ci] = '<select id="field_' . $i . '_' . ($ci - $ci_offset) . '" size="1" name="field_mimetype[]">' . "\n";
         $content_cells[$i][$ci] .= '    <option value=""></option>' . "\n";
-        $content_cells[$i][$ci] .= '    <option value="auto">auto-detect</option>' . "\n";
 
         if (is_array($available_mime['mimetype'])) {
             foreach ($available_mime['mimetype'] AS $mimekey => $mimetype) {