Fix off by one error in line number enumeration

pre_commit_hooks/check_merge_conflict.py

diff --git a/pre_commit_hooks/check_merge_conflict.py b/pre_commit_hooks/check_merge_conflict.py
index fc211bc..ac405b2 100644
--- a/pre_commit_hooks/check_merge_conflict.py
+++ b/pre_commit_hooks/check_merge_conflict.py
@@ -22,7 +22,7 @@
             for i, line in enumerate(inputfile):
                 for pattern in CONFLICT_PATTERNS:
                     if line.startswith(pattern):
-                        print(WARNING_MSG.format(pattern, filename, i))
+                        print(WARNING_MSG.format(pattern, filename, i + 1))
                         retcode = 1
 
     return retcode