[llvm] [llvm][Support] Add support for executing a detached process (PR #81708)

[Connor Sughrue via llvm-commits]

cpsughrue wrote:

Here is a before and after for the doxygen changes
![image](https://github.com/llvm/llvm-project/assets/55301806/ac539645-f74b-4276-86ff-5ab7662dfb03)
![image](https://github.com/llvm/llvm-project/assets/55301806/1a26df4a-2657-49f0-96de-0aac12a42f2e)


https://github.com/llvm/llvm-project/pull/81708