fix: meta -> Meta

Author: jdkato

testdata/features/frontmatter.feature

@@ -4,7 +4,7 @@ Feature: Frontmatter
     When I test "frontmatter"
     Then the output should contain exactly:
       """
-      test.md:2:9:meta.Title:'My document' should be in title case
+      test.md:2:9:Meta.Title:'My document' should be in title case
       test.md:3:23:vale.Annotations:'NOTE' left in text
       test.md:4:19:vale.Annotations:'XXX' left in text
       test.md:9:1:vale.Annotations:'NOTE' left in text

testdata/fixtures/frontmatter/.vale.ini

@@ -3,4 +3,4 @@ MinAlertLevel = suggestion
 
 [*.{md}]
 vale.Annotations = YES
-meta.Title = YES
+Meta.Title = YES