Misra's subspace of E_0 is totally separated

[Moniker1998]

Misra's subspace of E_0 is not extremally disconnected.

Also see #1060

[prabau]

An equivalent way, maybe slightly easier to present, is to give two disjoint open sets with intersecting closures.
In addition to $U$, let $V$ be the set of $a_{\alpha\beta}$ with $\alpha\in\omega_1\setminus A$. Then $a\in\overline{U}\cap\overline V$. But what you have is ok too.

Could you add the closely related trait P48 (totally separated) = true? (easy)

[Moniker1998]

@prabau it turns out that the theorem I want to add #1195 here already implies this space is not extremally disconnected

So instead, I will replace it by totally separated.

See also #1059