repl remembers non-loadable `:l` for `:r`

[roberth]

Describe the bug

A mistake I made when :log didn't work.

nix-repl> :l /nix/store/fiip84zv229vagk4i290f74jj383m2pf-vm-test-run-nixops-legacy-network.drv   
error: syntax error, unexpected ',', expecting ')'

nix-repl> :r
Loading '/nix/store/fiip84zv229vagk4i290f74jj383m2pf-vm-test-run-nixops-legacy-network.drv'...
error: syntax error, unexpected ',', expecting ')'

And now I've lost my symbols.

Steps To Reproduce

As above.

Expected behavior

The original :l specification is preserved, unless it did not exist, or unless loading it again can be expected to succeed.
The latter probably means

• not a store path
• not an immutable flakeref
• missing or bad files may be ok when user has write access

nix-env --version output

Additional context

Add any other context about the problem here.

Priorities

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