Multiple PATH arguments, truncation fix, fmt, clippy

[totph]

One bugfix when printing results, add support to search in more than one PATH, bring the README up to date, plus smaller fixups:

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Fix result truncation being off by one

The final '}' in a block was truncated when no line numbers were used.

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Accept multiple PATH arguments

Reading from stdin / '-' can be one of them.

Plus when searching in '.' avoid the middle dot like '/path/./src/foo.c' when converting to an absolute path.

Update README.md with new --help output and fix trailing whitespace.

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Fix alignment of -h/--help output

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Fix clippy warnings and a typo

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Run cargo fmt

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