add comment on contact tracing including non-cases

[avallecam]

use https://epiverse-trace.github.io/simulist/articles/vis-linelist.html#subset-contact-network-to-transmission-network

at:

tutorials-middle/episodes/superspreading-estimate.Rmd

Lines 188 to 208 in 6854f93

	::::::::::::::::::::: caution
	At `epicontacts::get_degree()` we use the argument `only_linelist = TRUE`.
	This is to count the number of secondary cases caused by all the observed infected individuals,
	which includes individuals in contacts and linelist data frames.
	:::::::::::::::::::::
	::::::::::::::::::::: spoiler
	### When to use 'only_linelist = FALSE'?
	The assumption that
	"the linelist will include all individuals in contacts and linelist"
	may not work for all situations.
	For example, if during the registry of observed infections,
	the contact data included more subjects than the ones available in the linelist data,
	then you need to consider only the individuals from the contact data.
	In that situation,
	at `epicontacts::get_degree()` we use the argument `only_linelist = FALSE`.