Create tags readme

tags/README.md

@@ -0,0 +1,60 @@
+Tree-sitter Tags
+=========================
+
+### Usage
+
+Compile some languages into your app, and declare them:
+
+```rust
+extern "C" tree_sitter_python();
+extern "C" tree_sitter_javascript();
+```
+
+Create a tag context. You need one of these for each thread that you're using for tag computation:
+
+```rust
+use tree_sitter_tags::TagsContext;
+
+let context = TagsContext::new();
+```
+
+Load some tagging queries from the `queries` directory of some language repositories:
+
+```rust
+use tree_sitter_highlight::TagsConfiguration;
+
+let python_language = unsafe { tree_sitter_python() };
+let javascript_language = unsafe { tree_sitter_javascript() };
+
+let python_config = HighlightConfiguration::new(
+    python_language,
+    &fs::read_to_string("./tree-sitter-python/queries/tags.scm").unwrap(),
+    &fs::read_to_string("./tree-sitter-python/queries/locals.scm").unwrap(),
+).unwrap();
+
+let javascript_config = HighlightConfiguration::new(
+    javascript_language,
+    &fs::read_to_string("./tree-sitter-javascript/queries/tags.scm").unwrap(),
+    &fs::read_to_string("./tree-sitter-javascript/queries/locals.scm").unwrap(),
+).unwrap();
+```
+
+Compute code navigation tags for some source code:
+
+```rust
+use tree_sitter_highlight::HighlightEvent;
+
+let tags = context.generate_tags(
+    &javascript_config,
+    b"class A { getB() { return c(); } }",
+    None,
+    |_| None
+);
+
+for tag in tags {
+    println!("kind: {:?}", tag.kind);
+    println!("range: {:?}", tag.range);
+    println!("name_range: {:?}", tag.name_range);
+    println!("docs: {:?}", tag.docs);
+}
+```