[mod] simple theme: remove vendor prefix of `width: max-content`

Remove no longer needed workarounds like `width: 1000px;`
and vendor prefix of max-content [1].

[1] https://developer.mozilla.org/en-US/docs/Web/CSS/max-content#browser_compatibility

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/static/themes/simple/src/less/search.less

@@ -194,9 +194,6 @@
     #main_index,
     #main_results {
       #categories_container {
-        width: 1000px;
-        width: -moz-max-content;
-        width: -webkit-max-content;
         width: max-content;
 
         .category {