Fix typos (#5998)

* Fix typos

* Update translation files appropriately

* Fix more 'fond's with 'found's

* Fix typos

* Fix duplicate message error

src/admesh/normals.cpp

@@ -189,7 +189,7 @@ void stl_fix_normal_directions(stl_file *stl)
     	if (head->next != tail) {
       		facet_num = head->next->facet_num;
             assert(facet_num < stl->stats.number_of_facets);
-      		if (norm_sw[facet_num] != 1) { // If facet is in list mutiple times
+      		if (norm_sw[facet_num] != 1) { // If facet is in list multiple times
         		norm_sw[facet_num] = 1; // Record this one as being fixed.
         		++ checked;
       		}