Typo: rename "litteral" with "literal"

@@ -5,6 +5,7 @@
 - Update xml dependency range
 - Implement PointDataSet for Chart
 - Implement PdfPageLabels
+- Typo: rename "litteral" with "literal"
 
 ## 3.7.4
 

@@ -144,17 +144,17 @@ class PdfNumList extends PdfDataType {
   int get hashCode => values.hashCode;
 }
 
-enum PdfStringFormat { binary, litteral }
+enum PdfStringFormat { binary, literal }
 
 class PdfString extends PdfDataType {
-  const PdfString(this.value, [this.format = PdfStringFormat.litteral]);
+  const PdfString(this.value, [this.format = PdfStringFormat.literal]);
 
   factory PdfString.fromString(String value) {
-    return PdfString(_string(value), PdfStringFormat.litteral);
+    return PdfString(_string(value), PdfStringFormat.literal);
   }
 
   factory PdfString.fromStream(PdfStream value,
-      [PdfStringFormat format = PdfStringFormat.litteral]) {
+      [PdfStringFormat format = PdfStringFormat.literal]) {
     return PdfString(value.output(), format);
   }
 
@@ -283,7 +283,7 @@ class PdfString extends PdfDataType {
         }
         s.putByte(0x3e);
         break;
-      case PdfStringFormat.litteral:
+      case PdfStringFormat.literal:
         s.putByte(40);
         _putTextBytes(s, value);
         s.putByte(41);
@@ -317,7 +317,7 @@ class PdfSecString extends PdfString {
   factory PdfSecString.fromString(
     PdfObject object,
     String value, [
-    PdfStringFormat format = PdfStringFormat.litteral,
+    PdfStringFormat format = PdfStringFormat.literal,
   ]) {
     return PdfSecString(
       object,
@@ -329,7 +329,7 @@ class PdfSecString extends PdfString {
   factory PdfSecString.fromStream(
     PdfObject object,
     PdfStream value, [
-    PdfStringFormat format = PdfStringFormat.litteral,
+    PdfStringFormat format = PdfStringFormat.literal,
   ]) {
     return PdfSecString(
       object,
@@ -342,7 +342,7 @@ class PdfSecString extends PdfString {
     return PdfSecString(
       object,
       PdfString._date(date),
-      PdfStringFormat.litteral,
+      PdfStringFormat.literal,
     );
   }
 

@@ -194,7 +194,7 @@ See https://github.com/DavBfr/dart_pdf/wiki/Fonts-Management
   /// Draw some text
   void putText(PdfStream stream, String text) {
     try {
-      PdfString(latin1.encode(text), PdfStringFormat.litteral).output(stream);
+      PdfString(latin1.encode(text), PdfStringFormat.literal).output(stream);
     } catch (_) {
       assert(() {
         print(_cannotDecodeMessage);