pantalaimon: install manuals

(cherry picked from commit f42a1d9df5a413cd80b36081922aaf3b7c33f8e6)

pkgs/applications/networking/instant-messengers/pantalaimon/default.nix

@@ -1,7 +1,7 @@
 { lib, stdenv, buildPythonApplication, fetchFromGitHub, pythonOlder,
   attrs, aiohttp, appdirs, click, keyring, Logbook, peewee, janus,
   prompt_toolkit, matrix-nio, dbus-python, pydbus, notify2, pygobject3,
-  setuptools, fetchpatch,
+  setuptools, fetchpatch, installShellFiles,
 
   pytest, faker, pytest-aiohttp, aioresponses,
 
@@ -56,6 +56,10 @@ buildPythonApplication rec {
     aioresponses
   ];
 
+  nativeBuildInputs = [
+    installShellFiles
+  ];
+
   # darwin has difficulty communicating with server, fails some integration tests
   doCheck = !stdenv.isDarwin;
 
@@ -63,6 +67,10 @@ buildPythonApplication rec {
     pytest
   '';
 
+  postInstall = ''
+    installManPage docs/man/*.[1-9]
+  '';
+
   meta = with lib; {
     description = "An end-to-end encryption aware Matrix reverse proxy daemon";
     homepage = "https://github.com/matrix-org/pantalaimon";