Inconsistent streamplot grid size

[ajdawson]

The documentation for streamplot says:

When density = 1, the domain is divided into a 25x25 grid — density
linearly scales this grid. ... For different densities in each
direction, use [density_x, density_y].

However the implementation is different. When density is 1 then the grid appears to be 30x30 (see streamplot.py L313), but if density is (1, 1) it is 25x25. I assume this is an error? Any idea @tonysyu?

[tonysyu]

Sorry it took me so long to reply to this issue, but it slipped under the radar. You're completely right. Most likely, the original implementation used 25x25, and I (presumably) thought that 30x30 looked better for some particular test case, so I changed it for the scalar variant. Personally, I'm fine with either. If you make a PR, I'll give my 👍 to however you choose to make it consistent.

[ajdawson]

@tonysyu - see #2700 for my fix