DISTROS: mark rolling release distros

These are ones that are unlikely to have back-ported curl patches.

Closes #13353

docs/DISTROS.md

@@ -10,7 +10,8 @@ SPDX-License-Identifier: curl
 
 Lots of organizations distribute curl packages to end users. This is a
 collection of pointers to where to learn more about curl on and with each
-distro.
+distro. Those marked *Rolling Release* typically run the latest version of curl
+and are therefore less likely to have back-ported patches to older versions.
 
 We discuss curl distro issues, patches and collaboration on the [curl-distros
 mailing list](https://lists.haxx.se/listinfo/curl-distros).
@@ -36,6 +37,8 @@ mailing list](https://lists.haxx.se/listinfo/curl-distros).
 
 ## Arch Linux
 
+*Rolling Release*
+
 - curl: https://archlinux.org/packages/core/x86_64/curl/
 - curl issues: https://gitlab.archlinux.org/archlinux/packaging/packages/curl/-/issues
 - curl security: https://security.archlinux.org/package/curl
@@ -43,6 +46,8 @@ mailing list](https://lists.haxx.se/listinfo/curl-distros).
 
 ## Buildroot
 
+*Rolling Release*
+
 - curl package source and patches: https://git.buildroot.net/buildroot/tree/package/libcurl
 - curl issues: https://bugs.buildroot.org/buglist.cgi?quicksearch=curl
 
@@ -52,6 +57,8 @@ mailing list](https://lists.haxx.se/listinfo/curl-distros).
 
 ## Clear Linux
 
+*Rolling Release*
+
 - curl: https://github.com/clearlinux-pkgs/curl
 - curl issues: https://github.com/clearlinux/distribution/issues
 
@@ -75,6 +82,8 @@ mailing list](https://lists.haxx.se/listinfo/curl-distros).
 
 (this is the official curl binaries for Windows shipped by the curl project)
 
+*Rolling Release*
+
 - curl: https://curl.se/windows/
 
 Issues and patches for this are managed in the main curl project.
@@ -112,17 +121,23 @@ Issues and patches for this are managed in the main curl project.
 
 ## Gentoo Linux
 
+*Rolling Release*
+
 - curl: https://packages.gentoo.org/packages/net-misc/curl
 - curl issues: https://bugs.gentoo.org/buglist.cgi?quicksearch=net-misc/curl
 - curl package sources and patches: https://gitweb.gentoo.org/repo/gentoo.git/tree/net-misc/curl/
 
 ## GNU Guix
 
+*Rolling Release*
+
 - curl: https://git.savannah.gnu.org/gitweb/?p=guix.git;a=blob;f=gnu/packages/curl.scm;hb=HEAD
 - curl issues: https://issues.guix.gnu.org/search?query=curl
 
 ## Homebrew
 
+*Rolling Release*
+
 - curl: https://formulae.brew.sh/formula/curl
 
 Homebrew's policy is that all patches and issues should be submitted upstream
@@ -130,6 +145,8 @@ unless it is very specific to Homebrew's way of packaging software.
 
 ## MacPorts
 
+*Rolling Release*
+
 - curl: https://github.com/macports/macports-ports/tree/master/net/curl
 - curl issues: https://trac.macports.org/query?0_port=curl&0_port_mode=%7E&0_status=%21closed
 - curl patches: https://github.com/macports/macports-ports/tree/master/net/curl/files
@@ -144,12 +161,16 @@ unless it is very specific to Homebrew's way of packaging software.
 
 ## MSYS2
 
+*Rolling Release*
+
 - curl: https://github.com/msys2/MINGW-packages/tree/master/mingw-w64-curl
 - curl issues: https://github.com/msys2/MINGW-packages/issues
 - curl patches: https://github.com/msys2/MINGW-packages/tree/master/mingw-w64-curl (`*.patch`)
 
 ## Muldersoft
 
+*Rolling Release*
+
 - curl: https://github.com/lordmulder/cURL-build-win32
 - curl issues: https://github.com/lordmulder/cURL-build-win32/issues
 - curl patches: https://github.com/lordmulder/cURL-build-win32/tree/master/patch
@@ -186,6 +207,8 @@ can also be used on other distributions
 
 ## OpenEmbedded / Yocto Project
 
+*Rolling Release*
+
 - curl: https://layers.openembedded.org/layerindex/recipe/5765/
 - curl issues: https://bugzilla.yoctoproject.org/
 - curl patches: https://git.openembedded.org/openembedded-core/tree/meta/recipes-support/curl
@@ -231,16 +254,22 @@ can also be used on other distributions
 
 ## vcpkg
 
+*Rolling Release*
+
 - curl: https://github.com/microsoft/vcpkg/tree/master/ports/curl
 - curl issues: https://github.com/microsoft/vcpkg/issues
 - curl patches: https://github.com/microsoft/vcpkg/tree/master/ports/curl (`*.patch`)
 
 ## Void Linux
 
+*Rolling Release*
+
 - curl: https://github.com/void-linux/void-packages/tree/master/srcpkgs/curl
 - curl issues: https://github.com/void-linux/void-packages/issues
 - curl patches: https://github.com/void-linux/void-packages/tree/master/srcpkgs/curl/patches
 
 ## Wolfi
 
+*Rolling Release*
+
 - curl: https://github.com/wolfi-dev/os/blob/main/curl.yaml