patch 8.2.0901: formatting CJK text isn't optimal

Problem:    Formatting CJK text isn't optimal.
Solution:   Properly break CJK lines. (closes #3875)
diff --git a/src/ops.c b/src/ops.c
index ea71edb..ca00c25 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -1967,7 +1967,10 @@
 		    && (!has_format_option(FO_MBYTE_JOIN)
 			|| (mb_ptr2char(curr) < 0x100 && endcurr1 < 0x100))
 		    && (!has_format_option(FO_MBYTE_JOIN2)
-			|| mb_ptr2char(curr) < 0x100 || endcurr1 < 0x100)
+			|| (mb_ptr2char(curr) < 0x100
+			    && !(enc_utf8 && utf_eat_space(endcurr1)))
+			|| (endcurr1 < 0x100
+			    && !(enc_utf8 && utf_eat_space(mb_ptr2char(curr)))))
 	       )
 	    {
 		// don't add a space if the line is ending in a space