doc: fix title/function name mismatch
Fix mismatch in title for napi_get_value_string_utf16
Fixes: https://github.com/nodejs/abi-stable-node/issues/243
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows [commit guidelines]
Affected core subsystem(s)
doc, n-api