"Unknown or incomplete command" message doesn't contain preceding slash

When trying to run an invalid command, the printout of the command in the resulting error message does not contain a slash (/) character before the command name.

This was not the case in 1.18.2.

To reproduce

Try to run a command that doesn't exist: /invalid

Expected behaviour

Unknown or incomplete command, see below for error
/invalid<--[HERE]

Observed behaviour

Unknown or incomplete command, see below for error
invalid<--[HERE]

Screenshots

Screenshots provided by Avoma

1.18.2 (Correct behaviour)

1.19 (Incorrect behaviour)