repl tab complete hints hide existing text

[adienes]

I noticed some weird new behavior, presumably caused by #51229, although strictly speaking I did not bisect it.

basically, some existing text is getting hidden when the autocomplete hint tries to go on top of it. MWE:

julia> AbstractFloat<ctrl-a>Complex

where the ctrl-a is only to move the cursor to the front of the input, upon typing Complex, the text AbstractFloat is hidden

[mbauman]

Duplicate of #51320, to be fixed by #51321