[mbr] Fix link in README (#47914)

Author: lambdageek

src/mono/sample/mbr/README.md

@@ -28,7 +28,7 @@ build.sh -s Mono+Libs /p:MonoMetadataUpdate=true
 
 For WebAssembly:
 
-Make sure `EMSDK_PATH` is set (see [workflow](../../../../../docs/workflow/building/libraries/webassembly-instructions.md))
+Make sure `EMSDK_PATH` is set (see [workflow](../../../../docs/workflow/building/libraries/webassembly-instructions.md))
 ```console
 build.sh --os browser /p:MonoMetadataUpdate=true
 ```