Added \begin and \end in block type latex

@@ -467,7 +467,7 @@ class BoldMd extends InlineMd {
 class LatexMathMultyLine extends InlineMd {
   @override
   RegExp get exp => RegExp(
-        r"\\\[(.*?)\\\]",
+        r"\\\[(.*?)\\\]|(\\begin.*?\\end{.*?})",
         dotAll: true,
       );
 
@@ -482,7 +482,7 @@ class LatexMathMultyLine extends InlineMd {
   ) {
     var p0 = exp.firstMatch(text.trim());
     p0?.group(0);
-    String mathText = p0?[1]?.toString() ?? "";
+    String mathText = p0?[1] ?? p0?[2] ?? "";
     var workaround = latexWorkaround ?? (String tex) => tex;
     return WidgetSpan(
       alignment: PlaceholderAlignment.baseline,

@@ -115,12 +115,13 @@ class MdWidget extends StatelessWidget {
               context,
               eachLn.replaceAllMapped(
                   RegExp(
-                    r"\\\[(.*)\\\]",
+                    r"\\\[(.*?)\\\]|(\\begin.*?\\end{.*?})",
                     multiLine: true,
                     dotAll: true,
                   ), (match) {
                 //
-                String body = match[1]?.replaceAll("\n", " ") ?? "";
+                String body =
+                    (match[1] ?? match[2])?.replaceAll("\n", " ") ?? "";
                 return "\\[$body\\]";
               }),
               style,