fix: force train split for json,csv,txt for test_datasets and misc doc changes (#3226)

* fix: force train split for json,csv,txt for test_datasets

* feat(doc): add info on mixing datasets for VLM

* feat(doc): max memory

* fix(doc): clarify lr groups

* fix: add info on vision not being dropped

* feat: add qwen3-vl to multimodal docs

* fix: add moe blocks to arch list

* feat(doc): improve mistral docs

* chore: add helpful link [skip-e2e]

* fix: add vram usage for mistral small

* Update link in docs/faq.qmd

Co-authored-by: salman <salman.mohammadi@outlook.com>

---------

Co-authored-by: Wing Lian <wing@axolotl.ai>
Co-authored-by: salman <salman.mohammadi@outlook.com>

examples/magistral/think/README.md

@@ -12,7 +12,7 @@ Before starting, ensure you have:
 Run the thinking model fine-tuning:
 
 ```bash
-axolotl train magistral-small-think-qlora.yaml
+axolotl train examples/magistral/think/magistral-small-think-qlora.yaml
 ```
 
 This config uses about 19.1 GiB VRAM.

examples/magistral/vision/README.md

@@ -21,7 +21,7 @@ Before starting, ensure you have:
 
 3. Run the fine-tuning:
    ```bash
-   axolotl train magistral-small-vision-24B-qlora.yml
+   axolotl train examples/magistral/vision/magistral-small-vision-24B-qlora.yml
    ```
 
 This config uses about 17GiB VRAM.

examples/mistral/mistral-small/README.md

@@ -0,0 +1,51 @@
+# Mistral Small 3.1/3.2 Fine-tuning
+
+This guide covers fine-tuning [Mistral Small 3.1](mistralai/Mistral-Small-3.1-24B-Instruct-2503) and [Mistral Small 3.2](mistralai/Mistral-Small-3.2-24B-Instruct-2506) with vision capabilities using Axolotl.
+
+## Prerequisites
+
+Before starting, ensure you have:
+- Installed Axolotl (see [Installation docs](https://docs.axolotl.ai/docs/installation.html))
+
+## Getting Started
+
+1. Install the required vision lib:
+    ```bash
+    pip install 'mistral-common[opencv]==1.8.5'
+    ```
+
+2. Download the example dataset image:
+   ```bash
+   wget https://huggingface.co/datasets/Nanobit/text-vision-2k-test/resolve/main/African_elephant.jpg
+   ```
+
+3. Run the fine-tuning:
+   ```bash
+   axolotl train examples/mistral/mistral-small/mistral-small-3.1-24B-lora.yml
+   ```
+
+This config uses about 29.4 GiB VRAM.
+
+## Dataset Format
+
+The vision model requires multi-modal dataset format as documented [here](https://docs.axolotl.ai/docs/multimodal.html#dataset-format).
+
+One exception is that, passing `"image": PIL.Image` is not supported. MistralTokenizer only supports `path`, `url`, and `base64` for now.
+
+Example:
+```json
+{
+    "messages": [
+        {"role": "system", "content": [{ "type": "text", "text": "{SYSTEM_PROMPT}"}]},
+        {"role": "user", "content": [
+            { "type": "text", "text": "What's in this image?"},
+            {"type": "image", "path": "path/to/image.jpg" }
+        ]},
+        {"role": "assistant", "content": [{ "type": "text", "text": "..." }]},
+    ],
+}
+```
+
+## Limitations
+
+- Sample Packing is not supported for multi-modality training currently.

examples/mistral/mistral-small/mistral-small-3.1-24B-lora.yml

@@ -39,7 +39,7 @@ wandb_name:
 wandb_log_model:
 
 gradient_accumulation_steps: 1
-micro_batch_size: 1
+micro_batch_size: 2
 num_epochs: 1
 optimizer: adamw_bnb_8bit
 lr_scheduler: cosine