patch 9.1.0217: regexp: verymagic cannot match before/after a mark

Problem:  regexp: verymagic cannot match before/after a mark
Solution: Correctly check for the very magic check (Julio B)

Fix regexp parser for \v%>'m and \v%<'m
Currently \v%'m works fine, but it is unable to match before or after
the position of mark m.

closes: #14309

Signed-off-by: Julio B <julio.bacel@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index ff54348..359ce5b 100644
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -1733,7 +1733,7 @@
 			    EMIT((int)n);
 			    break;
 			}
-			else if (c == '\'' && n == 0)
+			else if (no_Magic(c) == '\'' && n == 0)
 			{
 			    // \%'m  \%<'m  \%>'m
 			    EMIT(cmp == '<' ? NFA_MARK_LT :