Improve markdown default highlights

colors/highlite.vim

@@ -497,16 +497,18 @@ local highlight_groups = {
 	markdownH4          = {fg=green_dark, style='bold'},
 	markdownH5          = {fg=cyan, style='bold'},
 	markdownH6          = {fg=purple_light, style='bold'},
-	mkdBold             = 'SpecialChar',
-	mkdCode             = 'Comment',
-	mkdCodeDelimiter    = 'mkdBold',
-	mkdCodeStart        = 'mkdHeading',
+	mkdBold             = 'SpecialComment',
+	mkdCode             = 'Statement',
+	mkdCodeDelimiter    = 'Label',
+	mkdCodeStart        = 'mkdCodeDelimiter',
+	mkdCodeEnd          = 'mkdCodeStart',
 	mkdHeading          = 'Delimiter',
 	mkdItalic           = 'mkdBold',
 	mkdListItem         = 'Special',
-	mkdNonListItemBlock = {},
 	mkdRule             = 'Underlined',
-	texMathZoneY        = 'String',
+	texMathMatcher      = 'Number',
+	texMathZoneX        = 'Number',
+	texMathZoneY        = 'Number',
 
 	--[[ 4.3.20. Python ]]
 	pythonBrackets        = 'Delimiter',