Doc Update: Adds Suggestions for #6043

[starry48]

Adds Suggestions made in #6043

• [Not applied] Docstrings on all new or modified functions / classes
• [ ✅] Updated documentation
• [Not applied] Updated CHANGELOG.md (where appropriate)

1. Poetry Installation Link Redirecting to the instructions

• Fix made: Changes the link in the first step to take the user to the installation instructions

2. poetry shell command needs prerequisites installed

• Fix made: Changes the poetry shell command to poetry env activate which still creates the virtual environment without more packages being installed

3. Clarify textual --version requires poetry run

• Fix made: Clarified that the textual --version requires poetry run command to be able to see the latest version of textual.

4. Adding how to Run examples

• Fix made: Adding how to Run examples by explaining to use the poetry run python <SCRIPT_NAME.py>