Parse multiline expressions in f-strings #618

Job	Run time
coverage	6m 23s
lint	3m 2s
Rustfmt	7s
Rust unit tests (ubuntu-latest)	2m 56s
test (macos-latest, 3.8)	7m 39s
Rust unit tests (macos-latest)	2m 40s
typecheck	1m 40s
test (macos-latest, 3.9)	8m 28s
Rust unit tests (windows-latest)	3m 51s
docs	2m 13s
test (macos-latest, 3.10)	8m 12s
test (macos-latest, 3.11)	8m 22s
test (macos-latest, 3.12-dev)	10m 27s
test (ubuntu-latest, 3.8)	6m 43s
test (ubuntu-latest, 3.9)	6m 6s
test (ubuntu-latest, 3.10)	5m 44s
test (ubuntu-latest, 3.11)	5m 51s
test (ubuntu-latest, 3.12-dev)	7m 15s
test (windows-latest, 3.8)	7m 20s
test (windows-latest, 3.9)	8m 40s
test (windows-latest, 3.10)	7m 26s
test (windows-latest, 3.11)	8m 24s
test (windows-latest, 3.12-dev)	10m 0s
	2h 19m 29s

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