Enable numeric keys + bug fix

• ✨ Jumpy2 should handle many more labels/jump targets now via fallback numeric characters. These numeric characters are new to Jumpy2 and remain lower in priority by default since they are harder to type.
• 🐛 Fix label rendering bug at high numbers.
• 📝 Add note in README.md about more advanced/efficient wordPattern: [^\s]{1,3}. If you're reading this, you should probably try it!