fix string length in snprintf for ARP table to include null byte

tui/main.cpp

@@ -139,7 +139,7 @@ void arpMenu(WINDOW *window) {
     const char *arpStr = arpArray.constData();
     const char *arpMacStr = arpMacArray.constData();
 
-    snprintf(str, width + 4, formatStr, arpStr, arpMacStr);
+    snprintf(str, width + 5, formatStr, arpStr, arpMacStr);
     /*memcpy(str, arpStr, strlen(arpStr));
     memcpy(str + strlen(arpStr), " at ", 4);
     memcpy(str + strlen(arpStr) + 4, arpMacStr, strlen(arpMacStr));*/