tree-wide: unify Bash completions outputs (#103421)

Use $out/share/bash-completion/completions to store the Bash completions

pkgs/tools/security/pass/extensions/import.nix

@@ -38,7 +38,7 @@ in stdenv.mkDerivation rec {
 
   installFlags = [
     "PREFIX=$(out)"
-    "BASHCOMPDIR=$(out)/etc/bash_completion.d"
+    "BASHCOMPDIR=$(out)/share/bash-completion/completions"
   ];
 
   postFixup = ''

pkgs/tools/security/pass/extensions/update.nix

@@ -13,7 +13,7 @@ stdenv.mkDerivation rec {
 
   postPatch = ''
     substituteInPlace Makefile \
-      --replace "BASHCOMPDIR ?= /etc/bash_completion.d" "BASHCOMPDIR ?= $out/etc/bash_completion.d"
+      --replace "BASHCOMPDIR ?= /etc/bash_completion.d" "BASHCOMPDIR ?= $out/share/bash-completion/completions"
   '';
 
   dontBuild = true;