feat: add Honey syntax highlighting

tests/unit/syntax.rs

@@ -607,6 +607,47 @@ pub fn main() void {
     assert_eq!(kind_at(&cache, 3, local), None);
 }
 
+#[test]
+fn honey_highlights_declarations_literals_edits_and_markdown_fences() {
+    let source = "Point :: struct { x f64 }\n\
+                  add proc(a, b i32) i32 {\n\
+                      text := \"hello é\"\n\
+                      enabled := true\n\
+                      value := 42\n\
+                      # note\n\
+                      return a + b\n\
+                  }";
+    let mut cache = self::cache(source, "main.hon");
+    assert_eq!(cache.language(), Some("Honey"));
+    assert!(!cache.tree.as_ref().unwrap().root_node().has_error());
+    for (row, token, kind) in [
+        (0, "Point", SyntaxKind::Type),
+        (0, "struct", SyntaxKind::Keyword),
+        (0, "f64", SyntaxKind::Type),
+        (1, "add", SyntaxKind::Function),
+        (1, "proc", SyntaxKind::Keyword),
+        (1, "i32", SyntaxKind::Type),
+        (2, "hello é", SyntaxKind::String),
+        (3, "true", SyntaxKind::Keyword),
+        (4, "42", SyntaxKind::Number),
+        (5, "note", SyntaxKind::Comment),
+        (6, "return", SyntaxKind::Keyword),
+    ] {
+        assert_token(&cache, source, row, token, kind);
+    }
+    assert_eq!(kind_at(&cache, 6, 7), None);
+    let changed = source.replace("\"hello é\"", "7");
+    cache.update(&lines(&changed), Some(Path::new("main.hon")), 1);
+    assert_token(&cache, &changed, 2, "7", SyntaxKind::Number);
+    assert_fresh(&cache, &changed, "main.hon");
+    for tag in ["honey", "honeylang", "hon"] {
+        let markdown = format!("```{tag}\n{source}\n```");
+        let injected = self::cache(&markdown, "README.md");
+        assert_token(&injected, &markdown, 2, "add", SyntaxKind::Function);
+        assert_token(&injected, &markdown, 3, "hello é", SyntaxKind::String);
+    }
+}
+
 #[test]
 fn filenames_shebang_save_as_and_tsx_use_actual_grammar_identity() {
     let source = lines("\u{feff}#!/usr/bin/env python3\nreturn 42");