Add RTDETR Trainer (#2745)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: Laughing-q <1185102784@qq.com>
Co-authored-by: Kayzwer <68285002+Kayzwer@users.noreply.github.com>
Co-authored-by: Laughing <61612323+Laughing-q@users.noreply.github.com>

docs/models/rtdetr.md

@@ -35,6 +35,7 @@ from ultralytics import RTDETR
 
 model = RTDETR("rtdetr-l.pt")
 model.info()  # display model information
+model.train(data="coco8.yaml")   # train
 model.predict("path/to/image.jpg")  # predict
 ```
 
@@ -51,7 +52,7 @@ model.predict("path/to/image.jpg")  # predict
 |------------|--------------------|
 | Inference  | :heavy_check_mark: |
 | Validation | :heavy_check_mark: |
-| Training   | :x: (Coming soon)  |
+| Training   | :heavy_check_mark: |
 
 # Citations and Acknowledgements
 
@@ -70,4 +71,4 @@ If you use Baidu's RT-DETR in your research or development work, please cite the
 
 We would like to acknowledge Baidu and the [PaddlePaddle](https://github.com/PaddlePaddle/PaddleDetection) team for creating and maintaining this valuable resource for the computer vision community. Their contribution to the field with the development of the Vision Transformers-based real-time object detector, RT-DETR, is greatly appreciated.
 
-*Keywords: RT-DETR, Transformer, ViT, Vision Transformers, Baidu RT-DETR, PaddlePaddle, Paddle Paddle RT-DETR, real-time object detection, Vision Transformers-based object detection, pre-trained PaddlePaddle RT-DETR models, Baidu's RT-DETR usage, Ultralytics Python API*
+*Keywords: RT-DETR, Transformer, ViT, Vision Transformers, Baidu RT-DETR, PaddlePaddle, Paddle Paddle RT-DETR, real-time object detection, Vision Transformers-based object detection, pre-trained PaddlePaddle RT-DETR models, Baidu's RT-DETR usage, Ultralytics Python API*

docs/reference/yolo/utils/loss.md

@@ -8,6 +8,11 @@ keywords: Ultralytics, YOLO, loss functions, object detection, keypoint detectio
 :::ultralytics.yolo.utils.loss.VarifocalLoss
 <br><br>
 
+# FocalLoss
+---
+:::ultralytics.yolo.utils.loss.FocalLoss
+<br><br>
+
 # BboxLoss
 ---
 :::ultralytics.yolo.utils.loss.BboxLoss

docs/reference/yolo/utils/metrics.md

@@ -3,11 +3,6 @@ description: Explore Ultralytics YOLO's FocalLoss, DetMetrics, PoseMetrics, Clas
 keywords: YOLOv5, metrics, losses, confusion matrix, detection metrics, pose metrics, classification metrics, intersection over area, intersection over union, keypoint intersection over union, average precision, per class average precision, Ultralytics Docs
 ---
 
-# FocalLoss
----
-:::ultralytics.yolo.utils.metrics.FocalLoss
-<br><br>
-
 # ConfusionMatrix
 ---
 :::ultralytics.yolo.utils.metrics.ConfusionMatrix