Escape apostrophes in generated snippets

[StantonMatt]

Summary

• Keep single-quoted generated Cucumber Expression snippets when the expression can be represented safely.
• Use double-quoted Ruby snippets when the generated expression contains an apostrophe, with escaping for double quotes, backslashes, and interpolation markers.
• Preserve backslash escaping for single-quoted snippets and cover apostrophe, interpolation, and trailing-backslash cases.

Fixes #1710

Verification

• bundle exec rspec spec/cucumber/glue/snippet_spec.rb
• bundle exec rspec
• bundle exec cucumber
• bundle exec rubocop
• git diff --check

Local repros now print Then("Lucy hears Sean's message") and Then('Lucy hears trailing \\'), and both generated snippets compile with Ruby.

[luke-hill]

Unfortunately this is what we previously had and we refactored it out many many moons ago.

The desired output here is to instead use double quoted snippets. Which is the previous behaviour. So we should use single quotes (If we can), then failing that, use double quotes. This avoids any issues.

[StantonMatt]

Updated this to keep single-quoted snippets when the generated expression has no apostrophe, and switch to double-quoted snippets when it does. I reran the full RSpec suite and RuboCop on the touched files after pushing this.

[luke-hill]

These aren't cucumber expression snippets. They're all regular snippets

[StantonMatt]

You are right; I renamed those examples in 06591c7 so they refer to generated snippets rather than cucumber expression snippets.