gh-125008: Fix `tokenize.untokenize` roundtrip for `\n{{` (#125013) #623

Job	Run time
Change detection / Compute changed files	5s
Address sanitizer	9m 2s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.0.15)	1m 57s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.1.7)	2m 9s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.2.3)	1m 57s
Windows MSI${{ '' }}	0s
Check if generated files are up to date	2m 31s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.3.2)	2m 4s
Docs	0s
Hypothesis tests on Ubuntu	5m 23s
CIFuzz	0s
Thread sanitizer / Thread sanitizer	4m 32s
Thread sanitizer (free-threading) / Thread sanitizer	7m 25s
WASI / build and test	6m 4s
macOS / build and test (macos-14)	8m 33s
macOS / build and test (macos-13)	11m 17s
macOS (free-threading) / build and test (macos-14)	8m 39s
Ubuntu / build and test (ubuntu-22.04)	7m 52s
Ubuntu (free-threading) / build and test (ubuntu-22.04)	9m 38s
Windows / build (arm64)	2m 57s
Windows (free-threading) / build (arm64)	2m 40s
Windows / build and test (Win32)	15m 58s
Windows (free-threading) / build and test (Win32)	23m 32s
Windows / build and test (x64)	15m 26s
Windows (free-threading) / build and test (x64)	22m 35s
All required checks pass	2s
	2h 52m 18s

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