chore: fix bug in xtask doc gen #684

Job	Run time
check-needs-run	5s
Bindings - Synchronise	8m 16s
generate-job-matrix	1m 34s
Check - Check(windows-latest) - all features	5m 56s
Check - Test(windows-latest) - all features	6m 20s
Check - Check(macos-latest) - all features	2m 7s
Check - Test(macos-latest) - all features	6m 40s
Check - Build(ubuntu-latest) - all features	6m 36s
Check - Build(ubuntu-latest) - lua54,bevy_bindings,unsafe_lua_modules,mlua_serialize,mlua_macros,mlua_async,rhai,bevy/trace_tracy	6m 36s
Check - Build(ubuntu-latest) - lua54,core_functions,unsafe_lua_modules,mlua_serialize,mlua_macros,mlua_async,rhai,bevy/trace_tracy	6m 36s
Check - Build(ubuntu-latest) - lua54,unsafe_lua_modules,mlua_serialize,mlua_macros,mlua_async,rhai,bevy/trace_tracy	6m 36s
Check - Check(ubuntu-latest) - all features	2m 1s
Check - Docs(ubuntu-latest) - all features	6m 35s
Check - Test(ubuntu-latest) - all features	6m 36s
	1h 12m 34s

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