[DOCUMENTATION] Installation instructions list different environment name than in `environment.yml`

[jeipollack]

wf-psf/docs/source/installation.md

Lines 20 to 37 in ab991f4

	```bash
	conda env create -f environment.yml
	conda activate wavediff-env
	```
	## Installation Steps
	Clone the repository:
	```bash
	git clone https://github.com/CosmoStat/wf-psf.git
	```
	Create the recommended environment (if you haven't already):
	```bash
	conda env create -f environment.yml
	conda activate wavediff-env