CLEANUP: Fix a typo in fix_is_valid description
MsgType tag was misspelled.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index da108ab..cb4cd44 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -15630,7 +15630,7 @@
numeric
- checks the BeginString tag is the first tag with a valid FIX version
- checks the BodyLength tag is the second one with the right body length
- - checks the MstType tag is the third tag.
+ - checks the MsgType tag is the third tag.
- checks that last tag in the message is the CheckSum tag with a valid
checksum