Parses a function's own man-page comment header at call time and prints
it as a help menu on stdout, so the documentation that already generates
Section 5 of the manual becomes reachable from the shell.
Reads the .fish source rather than the generated docs/fish-config.md, so
it cannot go stale between a header edit and a docs rebuild. Walks
backwards from the `function` line to collect the header, which resolves
multi-header files (fish-deps, gi, y) without reimplementing
manualtools._block_identity.
Returns 1 only when argv[1] is not a help flag; every other path prints
and returns 0. A return of 1 hands control back to the caller's body.
Nothing calls it yet.
rootiest
9077d9837e