[doc] ignore conflict markers in gitmergeconflicts.adoc

Signed-off-by: Julia Evans <julia@jvns.ca>

Author: jvns

.gitattributes

@@ -14,6 +14,7 @@ CODE_OF_CONDUCT.md -whitespace
 /t/oid-info/* text eol=lf
 /Documentation/git-merge.adoc conflict-marker-size=32
 /Documentation/git-merge-file.adoc conflict-marker-size=32
+/Documentation/gitmergeconflicts.adoc conflict-marker-size=32
 /Documentation/gitk.adoc conflict-marker-size=32
 /Documentation/user-manual.adoc conflict-marker-size=32
 /t/t????-*.sh conflict-marker-size=32