Change create command build policy documentation

[czoido]

As explained in conan-io/conan#6131 the --build policy help message was the same for the commands create, test, install and workspace but the behavior for the create command by default was not to behave as --build=never but as --build=package name which could be misleading.

[danimtb]

reference should be clear enough for people to understand that it refers to the reference name or should it be <reference>?

Is that really the reference or the reference name?

[czoido]

reference should be clear enough for people to understand that it refers to the reference name or should it be <reference>?

Is that really the reference or the reference name?

Yes, I think that It will be more clear with package name, reference is confusing