Install shell completion support system-wide

- Supported shells (for system-wide completion) are bash, fish, and zsh;
  procs can also generate completions for elvish and powershell.

https://github.com/dalance/procs/tree/v0.14.1#shell-completion

rust-procs.spec

@@ -48,6 +48,9 @@ License:        Apache-2.0 AND BSD-3-Clause AND MIT AND MPL-2.0 AND Unicode-DFS-
 %doc CHANGELOG.md
 %doc README.md
 %{_bindir}/procs
+%{bash_completions_dir}/procs.bash
+%{fish_completions_dir}/procs.fish
+%{zsh_completions_dir}/_procs
 
 %prep
 %autosetup -n %{crate}-%{version} -p1
@@ -64,6 +67,15 @@ License:        Apache-2.0 AND BSD-3-Clause AND MIT AND MPL-2.0 AND Unicode-DFS-
 %install
 %cargo_install
 
+# generate and install shell completions
+target/rpm/procs --gen-completion-out bash > procs.bash
+target/rpm/procs --gen-completion-out fish > procs.fish
+target/rpm/procs --gen-completion-out zsh > _procs
+
+install -Dpm 0644 procs.bash -t %{buildroot}/%{bash_completions_dir}
+install -Dpm 0644 procs.fish -t %{buildroot}/%{fish_completions_dir}
+install -Dpm 0644 _procs -t %{buildroot}/%{zsh_completions_dir}
+
 %if %{with check}
 %check
 %cargo_test