docs(extensions): correct link to x-omitempty example

Author: Jamie Tanna

README.md

@@ -2676,7 +2676,7 @@ type ClientWithExtension struct {
 
 Notice that the `ComplexField` is still generated in full, but the type will then be ignored with JSON marshalling.
 
-You can see this in more detail in [the example code](examples/extensions/xgojsonignore/).
+You can see this in more detail in [the example code](examples/extensions/xomitempty/).
 
 ### `x-go-json-ignore` - when (un)marshaling JSON, ignore field(s)