Add jk-jeon/dragonbox to README Miscellaneous list (#1772)

* Initial plan

* Add Dragonbox entry to README Miscellaneous

Co-authored-by: fffaraz <895678+fffaraz@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: fffaraz <895678+fffaraz@users.noreply.github.com>

Author: Copilot

README.md

@@ -1298,6 +1298,7 @@ A curated list of awesome C++ (or C) frameworks, libraries, resources, and shiny
 * [cxx-prettyprint](https://github.com/louisdx/cxx-prettyprint) - A pretty printing library for C++ containers. [Boost]
 * [date](https://github.com/HowardHinnant/date) - A date and time library based on the C++11/14/17 <chrono> header. [MIT] [website](https://howardhinnant.github.io/date/date.html)
 * [D++ (DPP)](https://github.com/brainboxdotcc/DPP) - A lightweight, high performance and scalable C++ library for creating Discord Bots. [Apache2] [website](https://dpp.dev)
+* [Dragonbox](https://github.com/jk-jeon/dragonbox) - Reference implementation of a new float-to-string conversion algorithm in C++. [Apache2/BSL-1.0]
 * [DynaMix](https://github.com/iboB/dynamix) - A library which allows you to compose and modify objects at run time. [MIT]
 * [emio](https://github.com/Viatorus/emio) - A safe and fast high-level and low-level character input/output library. [MIT]
 * [faker-cxx](https://github.com/cieslarmichal/faker-cxx) - C++20 Faker library for generating fake (but realistic) data for testing and development. [MIT]