"fake build" alias for "fake run"

[matthid]

Description

We have now the fake.build website. So we should make fake build a thing.

[rmunn]

Another thought: if multiple verbs are added to FAKE in the future, it's possible that one or more of them may end up conflicting with someone's target name in their pre-existing build.fsx. E.g., they may have a target named test, lowercase, which would conflict with a hypothetical future fake test verb.

If more verbs are added to FAKE, it would probably be good to document how to run them, e.g. "If you already have a task named build, you can run it with fake run build."

[matthid]

In fake 5 we currently have no shortcut syntax, so we currently don't have this problem. You always have to write fake run at the moment...
But yeah if we decide to add shortcuts we inherit this problem.

[matthid]

I think fake build should be an alias for fake run build.fsx (including the default name build.fsx) this way the most common use-case is more natural. The positional (optional) argument can be the "target".

[matthid]

Implemented in #1770