doc: fix nits regarding stream utilities
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
- Unify headings.
- Conform method mentions with the style guide.
- Fix links.
### Readable.from()
-> ### stream.Readable.from()
heading change seems suboptimal and non-typical, but it seems it would be wrong to place this part with descriptions of Readable
instances or to leave it as is along with other stream.*
utilities, in incorrect structure and sorting place.