style-guide: Rewrite let-else section for clarity, without changing formatting

The section as written did not cover all cases, and left some of them
implicit. Rewrite it to systematically cover all cases. Place examples
immediately following the corresponding case.

In the process, reorder to move the simplest cases first: start with
single-line and add progressively more line breaks.

This does not change the meaning of the section at all, and in
particular does not change the defined style for let-else statements.

0 files changed, 0 insertions, 0 deletions