doc: update doc for new functions

docs/en/api/packages/convertor.md

@@ -955,7 +955,7 @@ func main() {
 
 ### <span id="ToUrlBase64">ToUrlBase64</span>
 
-<p>Convert a value to a string encoded in Url Base64. Error data of type "error" will also be encoded, and complex structures will be converted to a JSON-formatted string.</p>
+<p>Convert a value to a string encoded in url Base64. Error data of type "error" will also be encoded, and complex structures will be converted to a JSON-formatted string.</p>
 
 <b>Signature:</b>
 

docs/en/api/packages/slice.md

@@ -2565,4 +2565,35 @@ func main() {
     // Output:
     // okk
 }
+```
+
+### <span id="SetToDefaultIf">SetToDefaultIf</span>
+
+<p>Sets elements to their default value if they match the given predicate. It retains the positions of the elements in the slice. It returns slice of T and the count of modified slice items</p>
+
+<b>Signature:</b>
+
+```go
+func SetToDefaultIf[T any](slice []T, predicate func(T) bool) ([]T, int)
+```
+
+<b>Example:</b>
+
+```go
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/slice"
+)
+
+func main() {
+    strs := []string{"a", "b", "a", "c", "d", "a"}
+	modifiedStrs, count := slice.SetToDefaultIf(strs, func(s string) bool { return "a" == s })
+	
+    fmt.Println(modifiedStrs)
+	fmt.Println(count)
+	
+    // Output:
+	// [ b  c d ]
+	// 3
+}
 ```