ghci: the filename in :script <filename> doesn't support spaces.
## Summary
Write a brief description of the issue.
## Steps to reproduce
```bash
mkdir foo\ bar
echo putStrLn \"foo\" > foo\ bar/foo.hs
ghci
GHCi, version 8.6.5: http://www.haskell.org/ghc/ :? for help
Prelude> :script foo\ bar/foo.hs
syntax: :script <filename>
Prelude> :script "foo\ bar/foo.hs"
syntax: :script <filename>
Prelude> :script "foo bar/foo.hs"
syntax: :script <filename>
Prelude>
Leaving GHCi.
```
## Expected behavior
In ghci, path tab-completes with the space escaped with `\`. I'd expect this to work.
## Environment
* GHC version used: 8.6.5
* Operating System: Linux Mint
issue