Improve generator template

[ChaelCodes]

Description

Properly handle indentation on multi-line descriptions on the first generation.

Add new top-level documentation that steps you through the lifecycle of adding to the videos file.

# TODO: Add all talks - docs/ADDING_UNPUBLISHED_TALKS.md
# TODO: Reorder talks for schedule - docs/ADDING_SCHEDULES.md
# TODO: Add recordings - docs/ADDING_VIDEOS.md

The first line is added with the file (probably when keynotes are released) and stays until all talks are added.
The second line stays until the schedule is released and the order is updated.
The third line stays until the recordings are released and added.

Screenshots

Testing Steps

bin/rails g talk --balkanruby-2026 --description "This description is rather long.

It spans multiple paragraphs"

References

• closes #