Add patter[s]->pattern[s] to rare

diff --git a/codespell_lib/data/dictionary_rare.txt b/codespell_lib/data/dictionary_rare.txt
index f6f2a21..69937fd 100644
--- a/codespell_lib/data/dictionary_rare.txt
+++ b/codespell_lib/data/dictionary_rare.txt
@@ -101,6 +101,8 @@
 nickle->nickel
 ore->or
 panting->painting
+patter->pattern
+patters->patterns
 payed->paid
 planed->planned
 pleas->please