Ruby generator: multiline x-deprecated-reason emits invalid types.rb (latent)

[jeremy]

Follow-up from a resolved bot thread on #412 (discussion), filed for durable tracking.

Defect (latent / currently dormant)

ruby/scripts/generate-types.rb emits deprecation reasons on a single comment line:

puts "    # @deprecated #{schema['x-deprecated-reason'] || 'deprecated'}"
# ...and the per-attribute path:
puts "      #   @deprecated #{ps['x-deprecated-reason'] || 'deprecated'}"

If an x-deprecated-reason ever contains a newline, puts writes the later lines as bare Ruby source, producing a syntactically invalid types.rb. The reason is derived from OpenAPI descriptions without collapsing line breaks, so a multiline description would trigger this.

Why it isn't biting today

Scanned openapi.json: zero x-deprecated-reason values currently contain a newline, so rb-generate/rb-check are green. This is a robustness gap, not an active break.

Fix

Split the reason on \n and prefix every line with the comment leader (# / # @deprecated for the first, # for continuations), mirroring the Swift generator's deprecationDocLines treatment (added in #406). Add a generator unit test feeding a multiline reason.

Low priority — hardening only.