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

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

pkgs/tools/virtualization/awsebcli/default.nix

@@ -83,8 +83,8 @@ in with localPython.pkgs; buildPythonApplication rec {
   ];
 
   postInstall = ''
-    mkdir -p $out/etc/bash_completion.d
-    mv $out/bin/eb_completion.bash $out/etc/bash_completion.d
+    mkdir -p $out/share/bash-completion/completions
+    mv $out/bin/eb_completion.bash $out/share/bash-completion/completions/
   '';
 
   meta = with stdenv.lib; {

pkgs/tools/virtualization/nixos-container/default.nix

@@ -10,7 +10,7 @@ substituteAll {
     inherit utillinux;
 
     postInstall = ''
-      t=$out/etc/bash_completion.d
+      t=$out/share/bash-completion/completions
       mkdir -p $t
       cp ${./nixos-container-completion.sh} $t/nixos-container
     '';