docs: rename "doc" directory to "docs"

Also remove `CONTRIBUTING.adoc` and `FAQ.adoc` from project root since
GitHub knows to pick them up from the docs directory.

Fixes #2273

.github/PULL_REQUEST_TEMPLATE.md

@@ -15,7 +15,7 @@ pull-request.
 
 Also make sure to read the guidelines found at
 
-  https://github.com/nix-community/home-manager/blob/master/doc/contributing.adoc#sec-guidelines
+  https://github.com/nix-community/home-manager/blob/master/docs/contributing.adoc#sec-guidelines
 
 -->
 
@@ -35,7 +35,7 @@ Also make sure to read the guidelines found at
     {long description}
     ```
 
-    See [CONTRIBUTING](https://github.com/nix-community/home-manager/blob/master/doc/contributing.adoc#sec-commit-style) for more information and [recent commit messages](https://github.com/nix-community/home-manager/commits/master) for examples.
+    See [CONTRIBUTING](https://github.com/nix-community/home-manager/blob/master/docs/contributing.adoc#sec-commit-style) for more information and [recent commit messages](https://github.com/nix-community/home-manager/commits/master) for examples.
 
 - If this PR adds a new module
 

CONTRIBUTING.adoc

@@ -1 +0,0 @@
-doc/contributing.adoc

FAQ.adoc

@@ -1 +0,0 @@
-doc/faq.adoc

default.nix

@@ -1,7 +1,7 @@
 { pkgs ? import <nixpkgs> { } }:
 
 rec {
-  docs = with import ./doc { inherit pkgs; }; {
+  docs = with import ./docs { inherit pkgs; }; {
     html = manual.html;
     manPages = manPages;
     json = options.json;

modules/manual.nix

@@ -6,7 +6,7 @@ let
 
   cfg = config.manual;
 
-  docs = import ../doc { inherit lib pkgs; };
+  docs = import ../docs { inherit lib pkgs; };
 
 in