There is in fact a way to do this using Visual block mode. Simply pressing $A
in Visual block mode appends to the end of all lines in the selection. The appended text will appear on all lines as soon as you press Esc.
So this is a possible solution:
vip<C-V>$A,<Esc>
That is, in Normal mode, Visual select a paragraph vip
, switch to Visual block mode CTRLV, append to all lines $A
a comma ,
, then press Esc to confirm.
The documentation is at :h v_b_A
. There is even an illustration of how it works in the examples section: :h v_b_A_example
.