build/deb: fix auto-completion install paths (#25204)

Author: fjl

build/deb/ethereum/completions/bash_autocomplete renamed to build/deb/ethereum/completions/bash/geth

@@ -1,5 +1,5 @@
 build/bin/{{.BinaryName}} usr/bin
 {{- if eq .BinaryName "geth" }}
-build/deb/ethereum/completions/bash_autocomplete etc/bash_completion.d/geth
-build/deb/ethereum/completions/zsh_autocomplete usr/share/zsh/vendor-completions/_geth
+build/deb/ethereum/completions/bash/geth etc/bash_completion.d
+build/deb/ethereum/completions/zsh/_geth usr/share/zsh/vendor-completions
 {{end -}}