Prevent duplicated runs of examples

[caitlinch]

One of the examples contains the functions getPrevalence(), PoolReg(), PoolRegBayes(), and another 1 or two functions. When running checks during the development process, this example is run multiple times (once for each included function), increasing the time required for the checks process.

Reformat or restructure the example to reduce the run time. One option is to separate out the example into different examples (one per function). The preferred option would be to restructure the manual so all these functions appear on one manual page (and thus the example only runs once) – this option will be easier for the user to understand applying the functions in practice.

[caitlinch]

See this vignette on including multiple functions on the same page within the documentation (allowing you to link examples for different functions to a single documentation page).