Make ReactiveExpr available in pn.pane namespace

[MarcSkovMadsen]

As ReactiveExpr is explained as a pane I would expect it made available in the pn.pane namespace just as any other pane. But its not.

import panel as pn

pn.pane.ReactiveExpr

Traceback (most recent call last):
  File "C:\repos\private\panel-docs\app.py", line 25, in <module>
    pn.pane.ReactiveExpr

Please remove this friction and confusion by adding the ReactiveExpr to the pn.pane namespace. Or if its not a Pane then don't explain it as one.