The behaviour is better in the case someone has multiple levels of nested object fields defined in the mapping and like to define a single inner_hits definition that is two or more levels deep.
If someone wants inner hits on a nested field that is 2 levels deep the following would need to be defined:
```
{
...
"inner_hits" : {
"path" : {
"level1" : {
"inner_hits" : {
"path" : {
"level2" : {
"query" : { .... }
}
}
}
}
}
}
}
```
With this change the above can be defined as:
```
{
...
"inner_hits" : {
"path" : {
"level1.level2" : {
"query" : { .... }
}
}
}
}
```
Closes#9251
4393939f5e