[clang-format][c++2b] support removal of the space between auto and {} in P0849R8

Looks like the work of {D113393} requires manual clang-formatting intervention.
Removal of the space between `auto` and `{}`

Reviewed By: HazardyKnusperkeks, Quuxplusone

Differential Revision: https://reviews.llvm.org/D113826