[Feature Proposal] Add a built-in 'git whoami' command

[Giorgos Gasparis <gasp.giorgos@gmail.com>]

Hello Git team,

I would like to propose adding a native git whoami command to Git to
easily check the currently active identity.

Currently, users have to run two separate commands (git config
user.name and git config user.email) to check this. This is a frequent
friction point for developers balancing work and personal repositories
who want to double-check their active profile before committing.

To solve this locally, I currently use the following alias in my .gitconfig:

[alias] whoami = !echo "👤 $(git config user.name) | 📧 $(git config
user.email)"

Having a built-in command that provides this kind of unified,
single-line output natively (even as standard plain text without
emojis) would be a great quality-of-life improvement for the wider
community so they don't have to build custom aliases.

Thank you for your time and for maintaining Git, Georgios Gasparis