For example when loading parent_merge.xml:
```
WARNING: Attach conflict when attaching 'child' to 'parent_merge', policy is 'merge'
timestep: parent has 0.005, child has 0.002, taking the minimum
iterations: parent has 50, child has 100, taking the maximum
flag 'Damper': added from child
```
When loading parent_error.xml:
```
XML Error: Attach conflict when attaching 'child' to 'parent_error', policy is 'error'
timestep: parent has 0.005, child has 0.002
iterations: parent has 50, child has 100
Element 'attach', line 10
```
PiperOrigin-RevId: 933620810
Change-Id: Ib477863b5ef763474d27fb4be5a4148be1d5d500
Since the mjz format is just an archive for MJCF assets this seems like a sensible place. The upcoming mjz encoder will also need to make use of the full precision XML utility that is local to src/xml.
PiperOrigin-RevId: 912044746
Change-Id: I6a9fef24b1c3fec5b5edc3a8d4c8e22584273264