Fix mypyc regression with pretty #11150

Job	Run time
Test mypyc suite with 32-bit Python	10m 41s
Test suite with py38-ubuntu, mypyc-compiled	22m 11s
Test suite with py38-windows-64	34m 10s
Test suite with py39-ubuntu	28m 23s
Test suite with py310-ubuntu	26m 4s
Test suite with py311-ubuntu, mypyc-compiled	20m 36s
Test suite with py312-ubuntu, mypyc-compiled	22m 10s
mypyc runtime tests with py38-macos	7m 30s
mypyc runtime tests with py38-debug-build-ubuntu	7m 10s
Type check our own code (py38-ubuntu)	2m 6s
Type check our own code (py38-windows-64)	3m 9s
Formatting and code style with Black + ruff	43s
	3h 4m 53s

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