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/ruby.rs

@@ -0,0 +1,161 @@
+use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use language::{LanguageServerName, LspAdapter, LspAdapterDelegate};
+use lsp::LanguageServerBinary;
+use std::{any::Any, path::PathBuf, sync::Arc};
+
+pub struct RubyLanguageServer;
+
+#[async_trait]
+impl LspAdapter for RubyLanguageServer {
+    fn name(&self) -> LanguageServerName {
+        LanguageServerName("solargraph".into())
+    }
+
+    fn short_name(&self) -> &'static str {
+        "solargraph"
+    }
+
+    async fn fetch_latest_server_version(
+        &self,
+        _: &dyn LspAdapterDelegate,
+    ) -> Result<Box<dyn 'static + Any + Send>> {
+        Ok(Box::new(()))
+    }
+
+    async fn fetch_server_binary(
+        &self,
+        _version: Box<dyn 'static + Send + Any>,
+        _container_dir: PathBuf,
+        _: &dyn LspAdapterDelegate,
+    ) -> Result<LanguageServerBinary> {
+        Err(anyhow!("solargraph must be installed manually"))
+    }
+
+    async fn cached_server_binary(
+        &self,
+        _: PathBuf,
+        _: &dyn LspAdapterDelegate,
+    ) -> Option<LanguageServerBinary> {
+        Some(LanguageServerBinary {
+            path: "solargraph".into(),
+            env: None,
+            arguments: vec!["stdio".into()],
+        })
+    }
+
+    fn can_be_reinstalled(&self) -> bool {
+        false
+    }
+
+    async fn installation_test_binary(&self, _: PathBuf) -> Option<LanguageServerBinary> {
+        None
+    }
+
+    async fn label_for_completion(
+        &self,
+        item: &lsp::CompletionItem,
+        language: &Arc<language::Language>,
+    ) -> Option<language::CodeLabel> {
+        let label = &item.label;
+        let grammar = language.grammar()?;
+        let highlight_id = match item.kind? {
+            lsp::CompletionItemKind::METHOD => grammar.highlight_id_for_name("function.method")?,
+            lsp::CompletionItemKind::CONSTANT => grammar.highlight_id_for_name("constant")?,
+            lsp::CompletionItemKind::CLASS | lsp::CompletionItemKind::MODULE => {
+                grammar.highlight_id_for_name("type")?
+            }
+            lsp::CompletionItemKind::KEYWORD => {
+                if label.starts_with(':') {
+                    grammar.highlight_id_for_name("string.special.symbol")?
+                } else {
+                    grammar.highlight_id_for_name("keyword")?
+                }
+            }
+            lsp::CompletionItemKind::VARIABLE => {
+                if label.starts_with('@') {
+                    grammar.highlight_id_for_name("property")?
+                } else {
+                    return None;
+                }
+            }
+            _ => return None,
+        };
+        Some(language::CodeLabel {
+            text: label.clone(),
+            runs: vec![(0..label.len(), highlight_id)],
+            filter_range: 0..label.len(),
+        })
+    }
+
+    async fn label_for_symbol(
+        &self,
+        label: &str,
+        kind: lsp::SymbolKind,
+        language: &Arc<language::Language>,
+    ) -> Option<language::CodeLabel> {
+        let grammar = language.grammar()?;
+        match kind {
+            lsp::SymbolKind::METHOD => {
+                let mut parts = label.split('#');
+                let classes = parts.next()?;
+                let method = parts.next()?;
+                if parts.next().is_some() {
+                    return None;
+                }
+
+                let class_id = grammar.highlight_id_for_name("type")?;
+                let method_id = grammar.highlight_id_for_name("function.method")?;
+
+                let mut ix = 0;
+                let mut runs = Vec::new();
+                for (i, class) in classes.split("::").enumerate() {
+                    if i > 0 {
+                        ix += 2;
+                    }
+                    let end_ix = ix + class.len();
+                    runs.push((ix..end_ix, class_id));
+                    ix = end_ix;
+                }
+
+                ix += 1;
+                let end_ix = ix + method.len();
+                runs.push((ix..end_ix, method_id));
+                Some(language::CodeLabel {
+                    text: label.to_string(),
+                    runs,
+                    filter_range: 0..label.len(),
+                })
+            }
+            lsp::SymbolKind::CONSTANT => {
+                let constant_id = grammar.highlight_id_for_name("constant")?;
+                Some(language::CodeLabel {
+                    text: label.to_string(),
+                    runs: vec![(0..label.len(), constant_id)],
+                    filter_range: 0..label.len(),
+                })
+            }
+            lsp::SymbolKind::CLASS | lsp::SymbolKind::MODULE => {
+                let class_id = grammar.highlight_id_for_name("type")?;
+
+                let mut ix = 0;
+                let mut runs = Vec::new();
+                for (i, class) in label.split("::").enumerate() {
+                    if i > 0 {
+                        ix += "::".len();
+                    }
+                    let end_ix = ix + class.len();
+                    runs.push((ix..end_ix, class_id));
+                    ix = end_ix;
+                }
+
+                Some(language::CodeLabel {
+                    text: label.to_string(),
+                    runs,
+                    filter_range: 0..label.len(),
+                })
+            }
+            _ => return None,
+        }
+    }
+}