Merged PRs

dolt

8494: Fix bounds check in import scanner
fixes: #8495
The before code checks whether s.i is valid after doing the buffer access:
```
for ; unicode.IsSpace(rune(s.buf[s.i])); s.i++ {
if s.i >= s.fill {
s.read()
}
}
```
The after code inverts the check to make sure s.i is valid before indexing into the buffer.
```
for {
if s.i >= s.fill {
s.read()
}
if !unicode.IsSpace(rune(s.buf[s.i])) {
break
}
s.i++
}
```
8479: cross-schema foreign key support for doltgres tables
Depends on dolthub/go-mysql-server#2713

2717: push Distinct nodes below Sort nodes
This PR optimized queries like:
```
select distinct i from t order by i;
```
When there are many duplicate values in column i, it is much more efficient to eliminate duplicates first, then sort the results.
There are somewhat unrelated optimizations left as TODOs.
Optimize query: #8488
2716: Update Parser interface documentation
Updates documentation for the Parser interface to document the requirement that implementations must return vitess.ErrEmpty for empty queries. Without this, GMS will not handle empty queries correctly.
Related to: dolthub/doltgresql#884
2715: remove exchange node
These aren't used anywhere, so it's getting removed.
Partition still exists if we ever want to reimplement some version of this.
2713: Support for schema names in foreign key definitions
Adds schema names in many places required for foreign key operation in databases with schemas (doltgres)