semihosting link to risc-v details in document is changed
Description of problem:

Steps to reproduce:
1. Open https://gitlab.com/qemu-project/qemu/-/blob/master/docs/about/emulation.rst
2. Goto Supported Targets section
3. Click RISC-V link in the table
4. Got 404

New url looks like https://github.com/riscv-non-isa/riscv-semihosting/blob/main/riscv-semihosting.adoc
Additional information: