doc: fix nits in tools/doc/README.md
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
doc, tools
- Sync format schemes with the current doc state.
- Lowercase primitive types.
- Fix typos and unify the style.
- Remove tautological info.