Blender Git Loki

Fix T82407: Negative number input gives syntax error for velocities and
accelerations

Caused by rB45dbc38a8b15.

Above commit would place parentheses surrounding a block until the next
operator was found.
For velocities and accelerations though, the '/' in 'm/s' or 'ft/s'
should not be considered an operator.

Maniphest Tasks: T82407

Differential Revision: https://developer.blender.org/D9467