Idea: create table of IRAF tasks to specutils functions

Several issue tracker issues have been phrased as "replacement for IRAF task X". Perhaps we should include this explicitly in the docs? I.e. a table that maps IRAF tasks to either `specutils` functions/classes, says "will be in `specreduce`", or "not a function, but here's s snippet for how to do it?"

Or is that going to be too hard to keep up?

cc @crawfordsm @nmearl @keflavich

Start by reviewing the existing specutils documentation and issue tracker for issues phrased as replacements for IRAF tasks. Define the table’s mapping categories and how entries would stay current; done means the documentation contains an IRAF-task mapping to specutils functions or classes, specreduce, or an example snippet.

Written by the indexing model from the issue text.