This change moves the statement that `Proc#isolate` isn't yet exposed for Ruby users to the first time the method is mentioned. This is so that readers don't waste time trying to look it up in Ruby docs.
There was also unnecessary duplication:
```
Paragraph 1: "Given block will be isolated from outer scope by Proc#isolate."
Paragraph 2: "Given block will be isolated by Proc#isolate method"
```
So I combined the two sentences and slightly improved the wording for clarity.
Reintroduce removed empty line to fix indentation on rendered page
(the first line is _not_ indented despite the leading spaces,
and ends up "outdented" compared to the rest of the block).
Also add a missing "-".
This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.
[Feature #17100]
This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.
I hope this feature can help programmers from thread-safety issues.
