doc: add readable and writable property to Readable and Writable

[dexterleng]

Issue #21431

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[Trott]

It's a property, not a function, so it does not return a value.

[Trott]

It's a property, not a function, so it does not return a value.

[Trott]

Remove >

[Trott]

Remove >

[Trott]

Properties should be ordered alphabetically in the docs, so this is in the wrong place. It needs to appear above the other writable.writable* properties.

[Trott]

Properties should be ordered alphabetically in the docs, so this is in the wrong place. It needs to appear above the other readable.readable* properties.

[Trott]

Hi, @dexterleng! Welcome and thanks for the pull request! Documentation changes can attract a lot of comments, which sometimes surprises and even frustrates people. Try to be patient and to not get discouraged. Thanks again!

[dexterleng]

Oops. I forced pushed and broke the commit history. Opening a new PR.

[dexterleng]

#23933