Fix a typo in README.md (Turfjs#2313)

Co-authored-by: Rowan Winsemius <[email protected]>

README.md

@@ -61,7 +61,7 @@ Ports of Turf.js are available in:
 - [Swift](https://github.com/mapbox/turf-swift/) (iOS, macOS, tvOS, watchOS, Linux)
   - > Turf for Swift is **experimental** and its public API is subject to change. Please use with care.
 - [Dart/Flutter](https://github.com/dartclub/turf_dart) (Dart Web, Dart Native; Flutter for iOS, Android, macOS, Windows, Linux, Web)
-  - > Thr Turf for Dart port is still in progress, the implementation status can be found in the [README](https://github.com/dartclub/turf_dart#components).
+  - > The Turf for Dart port is still in progress, the implementation status can be found in the [README](https://github.com/dartclub/turf_dart#components).
 - - -
 
 ## Data in Turf