Completions: add support for doas as for sudo (nushell#10256)

# Description

Fixes nushell#2047 but for the `doas` command the same way as in nushell#8094

# User-Facing Changes
No breaking changes. If people not using `doas`, no difference at all.

# Tests
I have not added any tests since its using same logic as for "sudo". I
guess if something would go wrong in this part, sudo tests will cover
it?

# Additional context
As a nushell user I could not find a way to implement custom completion
for a "sudo like command". Since I can see `sudo` being hardcoded in
sources, this is what I propose.

~~Also I have almost zero knowledge of rust and this is definitely not
the clean way yet~~

---------

Co-authored-by: Stefan Holderbach <[email protected]>

.github/.typos.toml

@@ -11,3 +11,4 @@ Plasticos = "Plasticos"
 IIF = "IIF"
 numer = "numer"
 ratatui = "ratatui"
+doas = "doas"

crates/nu-cli/src/completions/command_completions.rs

@@ -234,7 +234,7 @@ pub fn is_passthrough_command(working_set_file_contents: &[(Vec<u8>, usize, usiz
         let cur_pos = find_non_whitespace_index(contents, last_pipe_pos);
 
         let result = match contents.get(cur_pos..) {
-            Some(contents) => contents.starts_with(b"sudo "),
+            Some(contents) => contents.starts_with(b"sudo ") || contents.starts_with(b"doas "),
             None => false,
         };
         if result {

crates/nu-cli/src/completions/completer.rs

@@ -136,7 +136,9 @@ impl NuCompleter {
                         for (flat_idx, flat) in flattened.iter().enumerate() {
                             let is_passthrough_command = spans
                                 .first()
-                                .filter(|content| content.as_str() == "sudo")
+                                .filter(|content| {
+                                    content.as_str() == "sudo" || content.as_str() == "doas"
+                                })
                                 .is_some();
                             // Read the current spam to string
                             let current_span = working_set.get_span_contents(flat.0).to_vec();