REPL: Add .clearhistory command

[SudhansuBandha]

What is the problem this feature will solve?

This feature allows users to clear REPL history from within the REPL itself, avoiding the need to manually locate and delete the history file. Similar to how Git Bash supports history -c.

What is the feature you are proposing to solve the problem?

This built-in command allows users to clear REPL history from within the REPL itself, avoiding the need to manually locate and delete the history file.

What alternatives have you considered?

No response

[SudhansuBandha]

I would be happy to work on an implementation if maintainers believe this would be a useful addition to the REPL.

[bitpshr]

Opened #64450 for this. It adds a .clearhistory command that clears the in-memory session history and truncates the persistent history file when one is configured.