rustdoc doesn't know to nest things into list items

[ben0x539]

see http://static.rust-lang.org/doc/0.6/core/task.html#enum-schedmode / https://github.com/mozilla/rust/blob/bdc182cc41c27/src/libcore/task/mod.rs#L82

rustdoc generates markdown like

#### Variants

* `DefaultScheduler` - Run task on the default scheduler
* `CurrentScheduler` - Run task on the current scheduler
* `ExistingScheduler(Scheduler)` - Run task on a specific scheduler
* `PlatformThread` - Tasks are scheduled on the main OS thread

The main OS thread is the thread used to launch the runtime which,
in most cases, is the process's initial thread as created by the OS.
* `SingleThreaded` - All tasks run in the same OS thread
* `ThreadPerCore` - Tasks are distributed among available CPUs
* `ThreadPerTask` - Each task runs in its own OS thread
* `ManualThreads(uint)` - Tasks are distributed among a fixed number of OS threads

so the list ends with the PlatformThread line and the rest is a run-on paragraph that happens to have asterisks in it.

[ben0x539]

Indenting the second part of the multi-line doc-comment with four spaces apparently tells markdown that we want multiple paragraphs in a single list item, but it looks weird in the .rs file and then there's paragraph elements in some list items and not others, which also looks weird (and inconsistent between markdown implementations):

Variants

• DefaultScheduler - Run task on the default scheduler
• CurrentScheduler - Run task on the current scheduler
• ExistingScheduler(Scheduler) - Run task on a specific scheduler

• PlatformThread - Tasks are scheduled on the main OS thread

  The main OS thread is the thread used to launch the runtime which, in most cases, is the process's initial thread as created by the OS.
• SingleThreaded - All tasks run in the same OS thread
• ThreadPerCore - Tasks are distributed among available CPUs
• ThreadPerTask - Each task runs in its own OS thread

• ManualThreads(uint) - Tasks are distributed among a fixed number of OS threads

I'm not sure what the desired html output here is in the first place (maybe paragraphs for every list item whether and css to squeeze them together?), but I suspect the doc comment is okay as it is and rustdoc ought to change.