nfpm.native_libs: Include new backend in docs/notes

Author: cognifloyd

docs/notes/2.31.x.md

@@ -66,12 +66,13 @@ Go now compiles with trimpath to strip sandbox paths from output, allowing for r
 Added a new experimental `pants.backend.experimental.nfpm.native_libs` backend to complement the [`nFPM`](https://nfpm.goreleaser.com/) backend (originally added in [pants 2.23](https://github.com/pantsbuild/pants/blob/main/docs/notes/2.23.x.md#new-nfpm)). `nFPM` builds system packages, but, unlike native packaging tools, does not inspect packaged binaries to automatically record package `depends` (aka `requires`). The nFPM Native Libs backend is meant to fill that feature gap, simplifying package dependency management.
 
 Initially, this backend only supports:
-- `rpm` packages (by inspecting the dependencies of `nfpm_rpm_package` targets;
+- `deb` and `rpm` packages (by inspecting the dependencies of `nfpm_deb_package` and `nfpm_rpm_package` targets);
 - native libraries packaged as wheels in `pex_binary` targets;
 - native libraries and binaries in the [`ELF`](https://en.wikipedia.org/wiki/Executable_and_Linkable_Format) format (used on linux);
 
 So, this backend provides a simplified set of features from these native packaging tools:
 - `rpm`: `elfdeps` analyzes ELF metadata and `rpmdeps` adds the requirements to the `.rpm` file.
+- `deb`: `${shlibs:Depends}` and similar debian control file substitutions are handled by `dh_shlibdeps` and `dpkg-shlibdeps` tooling.
 
 This backend should be platform-agnostic, allowing it to run wherever `pants` can run. To do this, it relies on the [`elfdeps`](https://github.com/python-wheel-build/elfdeps) [📦](https://pypi.org/project/elfdeps/) pure-python package (a "Python implementation of RPM `elfdeps`" with its pure-python dep [`pyelftools`](https://github.com/eliben/pyelftools) [📦](https://pypi.org/project/pyelftools/)) for analyzing `ELF` libraries.
 Then, for `deb` packages, this backend queries official [`debian`](https://packages.debian.org/search) or [`ubuntu`](https://packages.ubuntu.com/search) API (over HTTPS) to lookup which package(s) contain required libraries. Using the package search API avoids the local package metadata stores that can only find dependency packages if they are installed (such stores are not just distribution-specific, they are specific to a single release of a distribution).