Arrows in log messages

[danielballan]

Punting an aesthetic dicussion from #427 to a separate issue here. The current "direction" of a message is indicted by one of the symbols:

--->>>
<<<---

The clear visual weight to the right and left is a fair objective reason that was given for preferring this to →, ← or <-, ->.

What about solid filled arrows, ►, ◄? I think the direction is easier to see than the two rejected alternatives above, it's more compact, and I find it prettier.

[mrakitin]

+1 for →/←, however may not work in non-UTF8 encodings.

[danielballan]

In fact they are ASCII.

[danielballan]

On Slack, @ronpandolfi weighed in with the slightly wider filled arrow: ▶