chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/languages/src/lua.rs

@@ -0,0 +1,151 @@
+use anyhow::{anyhow, bail, Result};
+use async_compression::futures::bufread::GzipDecoder;
+use async_tar::Archive;
+use async_trait::async_trait;
+use futures::{io::BufReader, StreamExt};
+use language::{LanguageServerName, LspAdapterDelegate};
+use lsp::LanguageServerBinary;
+use smol::fs;
+use std::{any::Any, env::consts, path::PathBuf};
+use util::{
+    async_maybe,
+    github::{latest_github_release, GitHubLspBinaryVersion},
+    ResultExt,
+};
+
+#[derive(Copy, Clone)]
+pub struct LuaLspAdapter;
+
+#[async_trait]
+impl super::LspAdapter for LuaLspAdapter {
+    fn name(&self) -> LanguageServerName {
+        LanguageServerName("lua-language-server".into())
+    }
+
+    fn short_name(&self) -> &'static str {
+        "lua"
+    }
+
+    async fn fetch_latest_server_version(
+        &self,
+        delegate: &dyn LspAdapterDelegate,
+    ) -> Result<Box<dyn 'static + Send + Any>> {
+        let os = match consts::OS {
+            "macos" => "darwin",
+            "linux" => "linux",
+            "windows" => "win32",
+            other => bail!("Running on unsupported os: {other}"),
+        };
+        let platform = match consts::ARCH {
+            "x86_64" => "x64",
+            "aarch64" => "arm64",
+            other => bail!("Running on unsupported platform: {other}"),
+        };
+        let release = latest_github_release(
+            "LuaLS/lua-language-server",
+            true,
+            false,
+            delegate.http_client(),
+        )
+        .await?;
+        let version = &release.tag_name;
+        let asset_name = format!("lua-language-server-{version}-{os}-{platform}.tar.gz");
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| asset.name == asset_name)
+            .ok_or_else(|| anyhow!("no asset found matching {:?}", asset_name))?;
+        let version = GitHubLspBinaryVersion {
+            name: release.tag_name,
+            url: asset.browser_download_url.clone(),
+        };
+        Ok(Box::new(version) as Box<_>)
+    }
+
+    async fn fetch_server_binary(
+        &self,
+        version: Box<dyn 'static + Send + Any>,
+        container_dir: PathBuf,
+        delegate: &dyn LspAdapterDelegate,
+    ) -> Result<LanguageServerBinary> {
+        let version = version.downcast::<GitHubLspBinaryVersion>().unwrap();
+
+        let binary_path = container_dir.join("bin/lua-language-server");
+
+        if fs::metadata(&binary_path).await.is_err() {
+            let mut response = delegate
+                .http_client()
+                .get(&version.url, Default::default(), true)
+                .await
+                .map_err(|err| anyhow!("error downloading release: {}", err))?;
+            let decompressed_bytes = GzipDecoder::new(BufReader::new(response.body_mut()));
+            let archive = Archive::new(decompressed_bytes);
+            archive.unpack(container_dir).await?;
+        }
+
+        // todo!("windows")
+        #[cfg(not(windows))]
+        {
+            fs::set_permissions(
+                &binary_path,
+                <fs::Permissions as fs::unix::PermissionsExt>::from_mode(0o755),
+            )
+            .await?;
+        }
+        Ok(LanguageServerBinary {
+            path: binary_path,
+            env: None,
+            arguments: Vec::new(),
+        })
+    }
+
+    async fn cached_server_binary(
+        &self,
+        container_dir: PathBuf,
+        _: &dyn LspAdapterDelegate,
+    ) -> Option<LanguageServerBinary> {
+        get_cached_server_binary(container_dir).await
+    }
+
+    async fn installation_test_binary(
+        &self,
+        container_dir: PathBuf,
+    ) -> Option<LanguageServerBinary> {
+        get_cached_server_binary(container_dir)
+            .await
+            .map(|mut binary| {
+                binary.arguments = vec!["--version".into()];
+                binary
+            })
+    }
+}
+
+async fn get_cached_server_binary(container_dir: PathBuf) -> Option<LanguageServerBinary> {
+    async_maybe!({
+        let mut last_binary_path = None;
+        let mut entries = fs::read_dir(&container_dir).await?;
+        while let Some(entry) = entries.next().await {
+            let entry = entry?;
+            if entry.file_type().await?.is_file()
+                && entry
+                    .file_name()
+                    .to_str()
+                    .map_or(false, |name| name == "lua-language-server")
+            {
+                last_binary_path = Some(entry.path());
+            }
+        }
+
+        if let Some(path) = last_binary_path {
+            Ok(LanguageServerBinary {
+                path,
+                env: None,
+                arguments: Vec::new(),
+            })
+        } else {
+            Err(anyhow!("no cached binary"))
+        }
+    })
+    .await
+    .log_err()
+}