Fix bad indentation issue

Fixes #137

Signed-off-by: David Kwon <dakwon@redhat.com>

Author: dkwon17

src/extension.ts

@@ -212,6 +212,13 @@ function getScopeLevel(configurationKey : string, key : string) : ScopeInfo{
 
 function getIndentationRules(): LanguageConfiguration {
   return {
+    
+    // indentationRules referenced from:
+    // https://github.com/microsoft/vscode/blob/d00558037359acceea329e718036c19625f91a1a/extensions/html-language-features/client/src/htmlMain.ts#L114-L115
+    indentationRules: {
+      increaseIndentPattern: /<([-_\.A-Za-z0-9]+)(?=\s|>)\b[^>]*>(?!.*<\/\1>)|<!--(?!.*-->)|\{[^}"']*$/,
+      decreaseIndentPattern: /^\s*(<\/[-_\.A-Za-z0-9]+\b[^>]*>|-->|\})/
+    },
     onEnterRules: [
       {
         beforeText: new RegExp(`<([_:\\w][_:\\w-.\\d]*)([^/>]*(?!/)>)[^<]*$`, 'i'),