forked from aniani/vim
Make doc list-concatenation more clear as for += and extend(). 1. describe `+=` for list-concatenation more accurately 2. add `extend()` example for list-concatenation 3. Fix CI errors for missing helptags reference |+=| closes: #13983 Signed-off-by: qeatzy <qeatzy@users.noreply.github.com> Signed-off-by: Christian Brabandt <cb@256bit.org>