Fix #348: Allow ToolError to carry custom content and is_error #2324

Job	Run time
checks / readme-snippets	11s
checks / pre-commit	27s
checks / test (3.13, locked, windows-latest)	2m 37s
checks / test (3.10, locked, windows-latest)	2m 22s
checks / test (3.12, lowest-direct, ubuntu-latest)	50s
checks / test (3.12, locked, ubuntu-latest)	56s
checks / test (3.11, lowest-direct, ubuntu-latest)	54s
checks / test (3.11, locked, windows-latest)	2m 34s
checks / test (3.13, lowest-direct, ubuntu-latest)	45s
checks / test (3.11, locked, ubuntu-latest)	45s
checks / test (3.12, locked, windows-latest)	3m 27s
checks / test (3.12, lowest-direct, windows-latest)	3m 31s
checks / test (3.11, lowest-direct, windows-latest)	3m 8s
checks / test (3.13, lowest-direct, windows-latest)	2m 44s
checks / test (3.10, locked, ubuntu-latest)	47s
checks / test (3.10, lowest-direct, ubuntu-latest)	44s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 15s
checks / test (3.14, locked, ubuntu-latest)	2m 18s
checks / test (3.14, lowest-direct, windows-latest)	2m 42s
checks / test (3.10, lowest-direct, windows-latest)	2m 36s
checks / test (3.13, locked, ubuntu-latest)	47s
checks / test (3.14, locked, windows-latest)	3m 32s
all-green	5s
	39m 57s

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