Merge #21661: doc: Fix name of script guix-build

08151e1 doc: Fix name of script guix-build (Stephan Oeste)

Pull request description:

ACKs for top commit:
  hebasto:
    ACK 08151e1
  jarolrod:
    ACK 08151e1

Tree-SHA512: 50e52f91b489db6616b5c9a993474bc1b8c196c3cac4fd5ded7c8fece5a7d72f85d9f566ee6a3df56a132a22a91dd72801ce849ec5e430a7850ff05abcab6b37

Author: fanquake

contrib/guix/README.md

@@ -131,7 +131,7 @@ export JOBS=1 ADDITIONAL_GUIX_COMMON_FLAGS='--max-jobs=8'
 From the top of a clean Bitcoin Core repository:
 
 ```sh
-./contrib/guix/guix-build.sh
+./contrib/guix/guix-build
 ```
 
 After the build finishes successfully (check the status code please), compare