Bring back suggestion for splitting `<-` in a comparison

[varkor]

fn main() {
    if x<-1 {
    }
}

produces:

error: expected `{`, found `<-`

It would be nice if it produced a suggestion to split it up:

if x < -1 {

(This used to happen, but was broken in a previous change.)

[agnxy]

Hi @varkor I'd like to try this one. Just found the removed suggestion.

[agnxy]

@rustbot claim

[JohnTitor]

@rustbot assign @agnxy

Hmm, triagebot is not well...

[iluuu1994]

@agnxy It doesn't look like you're still working on this. Is it ok if I take over?