docs: fix typos in markdown files (#530)

* fix typos in configs/multimodal/llava/README.md

* fix typos in configs/multimodal/minigpt_4/README.md

configs/multimodal/llava/README.md

@@ -7,4 +7,4 @@ cd opencompass/multimodal/models/llava
 git clone https://github.com/haotian-liu/LLaVA.git
 ```
 
-Then prepare the environement according to the [install instruction](https://github.com/haotian-liu/LLaVA/tree/main#install)
+Then prepare the environment according to the [install instruction](https://github.com/haotian-liu/LLaVA/tree/main#install)
\ No newline at end of file

configs/multimodal/minigpt_4/README.md

@@ -7,7 +7,7 @@ cd opencompass/multimodal/models/minigpt_4
 git clone https://github.com/Vision-CAIR/MiniGPT-4.git
 ```
 
-Then prepare the environement according to this [doc](https://github.com/Vision-CAIR/MiniGPT-4)
+Then prepare the environment according to this [doc](https://github.com/Vision-CAIR/MiniGPT-4)
 
 ### Start evaluation