Fix rest operator syntax errors

[mlazowik]

These are caused by new syntax checking introduced by babylon.

"The single rest at the end only applies to binding let { x, ...y } = obj; and assignment ({ x, ...y } = obj)."

I'd say this really should be cherry picked into the stable branch.

Test plan

1. install [email protected]
2. see that things break
3. apply patch
4. things work
5. make sure all instances were fixed (I used \.\.\..*,.*\n.*= in IntelliJ regex format—find all ... followed by newline followed by =)

Issue #10199

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[mlazowik]

Update: the offending commit has been temporarily reverted: babel/babylon#154

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[ide]

Closing since this is a bug in Babylon to my knowledge and has been fixed upstream.

[mlazowik]

Well, this is not a bug in Babylon. They decided to postpone this syntax check until major release as it's essentially a breaking change, but it will be there.

I guess you are closing because even if this gets merged nothing will prevent people from making this syntax error in new code?

[ide]

Reopening because it's actually not clear to me how the trailing comma spec and the rest spec work together.

[javache]

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