docs: command line clang

*Please describe the question or issue you're facing with "Develop C and C with Clang on Ubuntu - Ubuntu for Developers".*

https://documentation.ubuntu.com/ubuntu-for-developers/tutorials/clang-use/#building-with-clang-directly

Documentation error

Currently reads
clang -o hello src/hello.cpp

Should read
clang++ -o hello src/hello.cpp

or

clang -x c++ -lstdc++ -o hello src/hello.cpp

* using the C++ compiler wrapper
clang++

* using the clang driver itself and explicitly declaring the c++ language and the c++ standard library
clang -x c++ -lstdc++

---
*Reported from: https://documentation.ubuntu.com/ubuntu-for-developers/tutorials/clang-use/*

Open the linked Clang tutorial at the “Building with Clang directly” section and review the command shown for src/hello.cpp. Update the documentation to use clang++ or the explicitly configured clang command, then verify the displayed command builds the example as described.

Written by the indexing model from the issue text.