Replace FileResource.is_binary with an encoding field #3657

Job	Run time
checks / readme-snippets	12s
checks / docs	45s
checks / pre-commit	1m 2s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 31s
checks / test (3.10, lowest-direct, windows-latest)	1m 53s
checks / test (3.10, locked, ubuntu-latest)	1m 28s
checks / test (3.11, lowest-direct, windows-latest)	1m 59s
checks / test (3.10, locked, windows-latest)	1m 58s
checks / test (3.12, lowest-direct, windows-latest)	1m 50s
checks / test (3.11, locked, ubuntu-latest)	1m 23s
checks / test (3.11, locked, windows-latest)	1m 38s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.13, lowest-direct, windows-latest)	2m 4s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 3s
checks / test (3.12, locked, windows-latest)	1m 54s
checks / test (3.13, locked, windows-latest)	1m 57s
checks / test (3.14, locked, ubuntu-latest)	1m 18s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 18s
checks / test (3.14, lowest-direct, windows-latest)	1m 48s
checks / test (3.13, locked, ubuntu-latest)	1m 17s
checks / test (3.14, locked, windows-latest)	1m 51s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 13s
checks / test (3.12, locked, ubuntu-latest)	1m 43s
all-green	4s
	34m 27s

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