Change config file location + Small fixes

[gAbelli]

Hi! I worked on some small changes and I wanted to propose them to you. Feel free to reject them or to suggest improvements. Here is what I did.

• I didn't particularly like to have the configuration file in ~/.gptrc for two reasons: (1) I don't like polluting my home folder too much and (2) the "rc" that you see for example in "bashrc" stands for "run commands" and is usually meant to identify a file that can be executed by a shell, but in our case the file is a yaml configuration file. So I moved it to ~/.config/gpt-cli/gpt.yml as it is quite common.
• I consequently updated the documentation, also adding information on how to run the program from anywhere.
• I also made a slight change in the way python handles the path to make it compatible with Windows.
• I added missing arguments in a formatted string.

Thank you for the great project, I hope I can contribute more in the future!

[kharvd]

Thanks for working on this! This is valuable feedback.

As is, this change is not backwards-compatible: it will break someone's config if they pull the repo. I wonder if we can fall back to using .gptrc if it exists

[gAbelli]

Thank you for your reply!
Yes I would say it's totally possible to make it check for both files, giving priority to ~/.config/gpt-cli/gpt.yml. I'll work on this later and update the pull request.

[gAbelli]

It should be good now. I tested it on both Linux and Windows.
Let me know if you find more things to improve!

[kharvd]

Nice, thanks!