root_source_file not supported in v0.15.2, but documents build demo has it

[yellowzq]

source

ref: https://zig.guide/build-system/zig-build#Hello Zig Build
version: zig 0.15.2

bug describe

.root_source_file is old and not supported in v0.15.2

error information

$zig-ai\helloworld> zig build
build.zig:6:10: error: no field named 'root_source_file' in struct 'Build.ExecutableOptions'
.root_source_file = b.path("src/main.zig"),
^~~~~~~~~~~~~~~~
C:\env\zig-x86_64-windows-0.15.2\lib\std\Build.zig:771:31: note: struct declared here
pub const ExecutableOptions = struct {
^~~~~~
referenced by:
runBuild__anon_32508: C:\env\zig-x86_64-windows-0.15.2\lib\std\Build.zig:2214:33
main: C:\env\zig-x86_64-windows-0.15.2\lib\compiler\build_runner.zig:366:29
4 reference(s) hidden; use '-freference-trace=6' to see all references