feat!: update the default renderer to thrasos

[maribethb]

The basics

• I validated my changes

The details

Proposed Changes

• Updates the default renderer to thrasos from geras
• Forces a test that relied on geras logic to explicitly specify its renderer
• Updates the documentation to note the new default

Reason for Changes

geras is the old style, thrasos has been our recommended renderer for a while now. each block has 1/3 fewer dom elements associated with it, so it should be more performant as well.

Test Coverage

updated

Documentation

updated

BREAKING CHANGES

This change only affects you if you intended to use the geras renderer but did not specify it explicitly in the options. We recommend that you use the thrasos renderer in this case. See the screenshots for comparisons; the changes are subtle enough that you do not necessarily have to update any of your visual resources. Because there are fewer dom elements, you may see increased performance on large workspaces.

If you wish to continue using the geras renderer, you need only specify the option when you inject Blockly.

above: thrasos (new default)

above: geras (old default)

[mikeharv]

🎉