Add a generate-all step and auto-generate settings.md (#5080)

## Summary

Ensures that `generate-all` generates both the JSON Schema and the
`settings.md` API reference.

crates/uv-dev/src/generate_all.rs

@@ -0,0 +1,30 @@
+//! Run all code and documentation generation steps.
+
+use anyhow::Result;
+
+use crate::{generate_json_schema, generate_options_reference};
+
+#[derive(clap::Args)]
+pub(crate) struct Args {
+    #[arg(long, default_value_t, value_enum)]
+    mode: Mode,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, clap::ValueEnum, Default)]
+pub(crate) enum Mode {
+    /// Update the content in the `configuration.md`.
+    #[default]
+    Write,
+
+    /// Don't write to the file, check if the file is up-to-date and error if not.
+    Check,
+
+    /// Write the generated help to stdout.
+    DryRun,
+}
+
+pub(crate) fn main(args: &Args) -> Result<()> {
+    generate_json_schema::main(&generate_json_schema::Args { mode: args.mode })?;
+    generate_options_reference::main(&generate_options_reference::Args { mode: args.mode })?;
+    Ok(())
+}