Vendor things

third-party/vendor/unicode-xid/README.md

@@ -0,0 +1,53 @@
+# unicode-xid
+
+Determine if a `char` is a valid identifier for a parser and/or lexer according to
+[Unicode Standard Annex #31](http://www.unicode.org/reports/tr31/) rules.
+
+[![Build Status](https://img.shields.io/github/workflow/status/unicode-rs/unicode-xid/CI/master)](https://github.com/unicode-rs/unicode-xid/actions?query=branch%3Amaster)
+
+[Documentation](https://unicode-rs.github.io/unicode-xid/unicode_xid/index.html)
+
+```rust
+extern crate unicode_xid;
+
+use unicode_xid::UnicodeXID;
+
+fn main() {
+    let ch = 'a';
+    println!("Is {} a valid start of an identifier? {}", ch, UnicodeXID::is_xid_start(ch));
+}
+```
+
+# features
+
+unicode-xid supports a `no_std` feature. This eliminates dependence
+on std, and instead uses equivalent functions from core.
+
+
+# changelog
+
+## 0.2.4
+
+- Update to Unicode 15.0.0
+- Replace `const` tables with `static` tables.
+
+## 0.2.3
+
+- Update to Unicode 14.0.0
+
+## 0.2.2
+
+- Add an ASCII fast-path
+
+## 0.2.1
+
+- Update to Unicode 13.0.0
+- Speed up lookup
+
+## 0.2.0
+
+- Update to Unicode 12.1.0.
+
+## 0.1.0
+
+- Initial release.