Problem: Cannot add a digraph with a leading space. It is not easy to list
existing digraphs.
Solution: Add setdigraph(), setdigraphlist(), getdigraph() and
getdigraphlist(). (closesvim/vim#8580)
6106504e9e
Use GA_APPEND_VIA_PTR in registerdigraph().
Use tv_list_append_*() in getdigraphlist_appendpair().
Put the error messages in digraph.c.
E196 is N/A.
Remove mentions about 'encoding' being non-Unicode.
Nvim doesn't support setting encoding=japan, so skip a test.
cbc54cf484
