Used f-strings instead of percent formatting.

[tahadnan]

This pull request modernizes the string formatting in the documentation and example files of prompt_toolkit by replacing % formatting with f-strings. This update enhances readability and aligns the code with Python's current best practices, as f-strings provide a more concise and efficient way to format strings.

Changes Made

• Replaced % formatting with f-strings in various documentation examples and code snippets.
• Improved readability by reducing concatenation and making formatting more consistent.

Motivation

Switching to f-strings is beneficial because:

• f-strings are more readable and intuitive, especially for beginners.
• They improve code maintainability by reducing the need for tuple wrapping in cases of single variables.
• f-strings offer slight performance improvements over % formatting, which is valuable for code examples in a widely-used library like prompt_toolkit.

Testing

• Ran modified examples to confirm they work as expected with the updated f-string formatting.
• No functional changes to the examples' behavior, only a formatting improvement.

Additional Notes

No new dependencies or additional code changes are introduced. This PR solely focuses on modernizing string formatting in examples.

[jonathanslenders]

I prefer to not merge this. In many cases it's fine, but I see you also changed the formatting approach of the HTML() class, which will result in injection vulnerabilities or broken code due to incorrect escaping. We need PEP 750 for this.

I'd also prefer if the replacing of %-style formatting with f-strings were not done in the same PR as typo corrections, and if the replacement was performed automatically with a tool like pyupgrade. That way, the replacement is only done in places where it is fine.

[tahadnan]

So should I just close this PR?

[jonathanslenders]

Yes please, but thanks for the effort anyway!

Regarding the commit with the typos, one typo is a typo, the other isn't. It is "Vertica" not "vertical". Feel free to create a separate PR for this.
About the formatting, I'll try to remember doing pyupgrade over the codebase on the next change.

[tahadnan]

Great! thanks for the smooth communication and I really appreciate this project guys, keep up the good work.