ref(colors): update vimtex group names

Vimtex recently had a 2.0 release, and so now this template must also
update the names of the changed groups to match.

colors/highlite.vim

@@ -549,9 +549,6 @@ local highlight_groups = {
 	mkdItalic           = 'mkdBold',
 	mkdListItem         = 'Special',
 	mkdRule             = 'Underlined',
-	texMathMatcher      = 'Number',
-	texMathZoneX        = 'Number',
-	texMathZoneY        = 'Number',
 
 	--[[ 4.3.20. Python ]]
 	pythonBrackets        = 'Delimiter',
@@ -667,6 +664,12 @@ local highlight_groups = {
 	gitrebaseSquash = 'Macro',
 	gitrebaseSummary = 'Normal',
 
+	--[[ 4.3.35. Vimtex ]]
+	texMathGroup   = 'Number',
+	texMathSub     = 'Number',
+	texMathRegionX = 'Number',
+	texMathRegionY = 'Number',
+
 	--[[ 4.4. Plugins
 		Everything in this section is OPTIONAL. Feel free to remove everything
 		here if you don't want to define it, or add more if there's something