Fix misspelling

passes/pmgen/README.md

diff --git a/passes/pmgen/README.md b/passes/pmgen/README.md
index 0856c9b..2f5b8d0 100644
--- a/passes/pmgen/README.md
+++ b/passes/pmgen/README.md
@@ -352,7 +352,7 @@
     subpattern tail
     ...
 
-Subpatterns cann be called recursively.
+Subpatterns can be called recursively.
 
 If a `subpattern` statement is preceded by a `fallthrough` statement, this is
 equivalent to calling the subpattern at the end of the preceding block.