errors: format "abort: " text in a new Abort.format() method
This remove some duplication we had.
Differential Revision: https://phab.mercurial-scm.org/D9348
{
"version": 1,
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"project_url": "https://mercurial-scm.org/",
"repo": "..",
"branches": ["default", "stable"],
"environment_type": "virtualenv",
"show_commit_url": "https://www.mercurial-scm.org/repo/hg/rev/",
"benchmark_dir": "benchmarks",
"env_dir": "../.asv/env",
"results_dir": "../.asv/results",
"html_dir": "../.asv/html"
}