docs(README): add further information to footnotes

Author: freshgum-bubbles

README.md

@@ -110,7 +110,7 @@ Released under [MIT](./LICENSE) by [@freshgum](https://github.com/freshgum-bubbl
   P.S. Future maintainers: these footnotes are in order of *addition*, not appearance throughout the document.
   The ordering doesn't really matter anyway, as GitHub automatically sorts them in order of appearance (or so it seems).
 -->
-[^1]: Tested on 23/11/2023.  [A lot of work](https://github.com/search?q=repo%3Afreshgum-bubbles%2Ftypedi+bundle+size&type=commits) is made to reduce the size of the bundle *(a lot of work has also been inlined into other, non-related commits)*.
+[^1]: Tested on 23/11/2023.  [A lot of work](https://github.com/search?q=repo%3Afreshgum-bubbles%2Ftypedi+bundle+size&type=commits) is made to reduce the size of the bundle *(a lot of work has also been inlined into other, non-related commits)*.  Note that bundle size tests are performed by copying the minified `typedi.min.mjs` file into [ByteSizeMatters](https://freshgum-bubbles.github.io/bytesizematters/) -- there are most likely better ways to test this.  Investigation on reducing bundle size is then performed by formatting the minified file with Prettier, and assessing the bundle for unnecessary code / possible refactors; this is done iteratively until I am unable to find any further code size optimizations (which would not negatively affect performance / result in breaking changes).  An example of a trick used to reduce the bundle size is name mangling: the [Rollup configuration file](./rollup.config.mjs) contains code to minify certain members of internal classes (such as `VisitorCollection`).
 [^2]: No *runtime* dependencies are included.  The only dependency of this package is [type-fest](https://github.com/sindresorhus/type-fest) (which only provides TypeScript types which are used internally).  This dependency has been [version-locked](https://github.com/freshgum-bubbles/typedi/blob/develop/package.json) to ensure any breaches of that package's security does not impact anyone using this package.  Any updates are checked and verified to ensure they do not contain malicious code.
 [^3]: This mainly refers to the package's standard container-based interface, which makes testing easy (as you can replace services and values at any time).  Further work is being done on a more featureful testing suite, which would be able to simplify the overall testing process.
 [^4]: I haven't counted each one, but I'd say that the package exports ~40 types (as of writing: 23/11/2023); a lot of the safety is provided through typing, as opposed to unnecessary runtime checks, which affect performance and code size.