`_` is not supported in literals after the comma

[ssoelvsten]

I tried to create a module with the following program, which I thought would work as intended after #57 / #82 ?

3.1415926535_8979323846_2643383279_5028841971_6939937510_5820974944_5923078164_0628620899_8628034825_3421170679

I tried it in utop and it seems to be supported in OCaml.