doc: add section for FUSE

doc/builders/packages/fuse.section.md

@@ -0,0 +1,19 @@
+# FUSE {#sec-fuse}
+
+Some packages rely on
+[FUSE](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) to provide
+support for additional filesystems not supported by the kernel.
+
+In general, FUSE software are primarily developed for Linux but many of them can
+also run on macOS. Nixpkgs supports FUSE packages on macOS, but it requires
+[macFUSE](https://osxfuse.github.io) to be installed outside of Nix. macFUSE
+currently isn't packaged in Nixpkgs mainly because it includes a kernel
+extension, which isn't supported by Nix outside of NixOS.
+
+If a package fails to run on macOS with an error message similar to the
+following, it's a likely sign that you need to have macFUSE installed.
+
+    dyld: Library not loaded: /usr/local/lib/libfuse.2.dylib
+    Referenced from: /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs
+    Reason: image not found
+    [1]    92299 abort      /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs

doc/builders/packages/index.xml

@@ -12,6 +12,7 @@
  <xi:include href="emacs.section.xml" />
  <xi:include href="firefox.section.xml" />
  <xi:include href="fish.section.xml" />
+ <xi:include href="fuse.section.xml" />
  <xi:include href="ibus.section.xml" />
  <xi:include href="kakoune.section.xml" />
  <xi:include href="linux.section.xml" />