feat(defaults): enable diffopt "linematch" #32346

test/old/testdir/setup.vim

@@ -4,6 +4,7 @@ if exists('s:did_load')
   set complete=.,w,b,u,t,i
   set define=^\\s*#\\s*define
   set directory^=.
+  set diffopt=internal,filler,closeoff
   set display=
   set fillchars=vert:\|,foldsep:\|,fold:-
   set formatoptions=tcq