Modify readme file

Author: timandy

README.md

@@ -68,6 +68,7 @@ In general, the more complex the operation you want to perform on the data, the
 - asEnumerable
 - average
 - cast
+- chunk
 - concat
 - contains
 - count
@@ -148,6 +149,20 @@ In general, the more complex the operation you want to perform on the data, the
 - thenBy
 - thenByDescending
 
+## API of Index
+- fromStart
+- fromEnd
+- getValue
+- isFromEnd
+- getOffset
+
+## API of Range
+- startAt
+- endAt
+- getStart
+- getEnd
+- getOffsetAndLength
+
 ## Tuple classes
 - Tuple1
 - Tuple2

README_CN.md

@@ -68,6 +68,7 @@ LINQ 查询与 Stream API 相比也具有一定优势：
 - asEnumerable
 - average
 - cast
+- chunk
 - concat
 - contains
 - count
@@ -148,6 +149,20 @@ LINQ 查询与 Stream API 相比也具有一定优势：
 - thenBy
 - thenByDescending
 
+## Index 的 API
+- fromStart
+- fromEnd
+- getValue
+- isFromEnd
+- getOffset
+
+## Range 的 API
+- startAt
+- endAt
+- getStart
+- getEnd
+- getOffsetAndLength
+
 ## 元组类
 - Tuple1
 - Tuple2