feat: vcs, color, and message format native completion

Author: nooma-42

src/bin/cargo/cli.rs

@@ -633,9 +633,10 @@ See '<cyan,bold>cargo help</> <cyan><<command>></>' for more information on a sp
         )
         .arg(flag("quiet", "Do not print cargo log messages").short('q').global(true))
         .arg(
-            opt("color", "Coloring: auto, always, never")
+            opt("color", "Coloring")
                 .value_name("WHEN")
-                .global(true),
+                .global(true)
+                .value_parser(["auto", "always", "never"]),
         )
         .arg(
             Arg::new("directory")

src/bin/cargo/commands/locate_project.rs

@@ -8,11 +8,9 @@ pub fn cli() -> Command {
         .about("Print a JSON representation of a Cargo.toml file's location")
         .arg(flag("workspace", "Locate Cargo.toml of the workspace root"))
         .arg(
-            opt(
-                "message-format",
-                "Output representation [possible values: json, plain]",
-            )
-            .value_name("FMT"),
+            opt("message-format", "Output representation")
+                .value_name("FMT")
+                .value_parser(["json", "plain"]),
         )
         .arg_silent_suggestion()
         .arg_manifest_path()

src/cargo/util/command_prelude.rs

@@ -361,7 +361,18 @@ pub trait CommandExt: Sized {
     }
 
     fn arg_message_format(self) -> Self {
-        self._arg(multi_opt("message-format", "FMT", "Error format"))
+        self._arg(
+            multi_opt("message-format", "FMT", "Error format")
+                .value_parser([
+                    "human",
+                    "short",
+                    "json",
+                    "json-diagnostic-short",
+                    "json-diagnostic-rendered-ansi",
+                    "json-render-diagnostics",
+                ])
+                .value_delimiter(','),
+        )
     }
 
     fn arg_build_plan(self) -> Self {