gopass: add completions and manpage

Closes #95306.

Signed-off-by: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Signed-off-by: BrewTestBot <1589480+BrewTestBot@users.noreply.github.com>

Formula/gopass.rb

@@ -23,6 +23,11 @@ class Gopass < Formula
 
   def install
     system "make", "install", "PREFIX=#{prefix}/"
+
+    bash_completion.install "bash.completion" => "gopass.bash"
+    fish_completion.install "fish.completion" => "gopass.fish"
+    zsh_completion.install "zsh.completion" => "_gopass"
+    man1.install "gopass.1"
   end
 
   test do