perms.m: Small cleanups for Octave coding conventions (bug #60364) * perms.m: Wrap long lines in documentation to < 80 characters. Change output in documentation example to match what Octave actually produces. Use true/false for boolean variable "unique_v" rather than 0/1. Cuddle parentheses when doing indexing and use a space when calling a function. Add FIXME notes requesting an explanation of the apparently complicated algorithm being used for permutations and unque permutations. Remove period at end of error() message text per Octave conventions. Change BIST input validation to more precisely check error() message.

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