fix(scripts): parse wrapped Author(s) lines in render-seps (#3178)

The Author(s) regex used `.` to capture the field value, which does not
match newlines. When an author list wrapped onto an indented continuation
line, every author after the first line was silently dropped from the
generated docs/seps/*.mdx table, leaving a dangling comma in the cell.

Capture the first line plus any indented continuation lines that do not
begin a new list item, and collapse interior whitespace when the value is
used. Regenerated the three affected SEP documents: 2322 (was losing 1 of
3 authors), 1865 (6 of 9), and 2575 (2 of 5).

Co-authored-by: Gabriel Zimmerman <gabez@Gabriels-MacBook-Pro.local>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>