[minor] missing static on lib internal

levenshtein.hpp

@@ -20,7 +20,7 @@
 #include <utility>
 #include <queue>
 
-unsigned int levenshtein_get(unsigned int * const *map, int px, int py)
+static unsigned int levenshtein_get(unsigned int * const *map, int px, int py)
 {
     if (px == -1 && py == -1)
         return 0;