Fix documentation reference for write function

Updated reference from '._writev()' to '._write()' in documentation.

Signed-off-by: Muhammad Ahmed <104449961+ahmedhere@users.noreply.github.com>

Author: ahmedhere

apps/site/pages/en/learn/modules/backpressuring-in-streams.md

@@ -678,7 +678,7 @@ if (chunk.contains('b')) {
 callback();
 ```
 
-There are also some things to look out for when implementing [`._writev()`][].
+There are also some things to look out for when implementing [`._write()`][].
 The function is coupled with [`.cork()`][], but there is a common mistake when
 writing: