Merge nervosnetwork#3773

3773: [db] fix comment typos r=zhangsoledad a=StrayLittlePunk

### What problem does this PR solve?

fix comment typos 

### What is changed and how it works?

What's Changed:

### Related changes

- use `iterator` instead of `interator`
### Check List

- Unit test
- Integration test


```release-note
Title Only: Include only the PR title in the release note.
```



Co-authored-by: stray little punk <[email protected]>

db/src/iter.rs

@@ -10,14 +10,14 @@ pub use rocksdb::{DBIterator as DBIter, Direction, IteratorMode};
 
 /// An iterator over a column family, with specifiable ranges and direction.
 pub trait DBIterator {
-    /// Opens an interator using the provided IteratorMode.
+    /// Opens an iterator using the provided IteratorMode.
     /// This is used when you want to iterate over a specific ColumnFamily
     fn iter(&self, col: Col, mode: IteratorMode) -> Result<DBIter> {
         let opts = ReadOptions::default();
         self.iter_opt(col, mode, &opts)
     }
 
-    /// Opens an interator using the provided IteratorMode and ReadOptions.
+    /// Opens an iterator using the provided IteratorMode and ReadOptions.
     /// This is used when you want to iterate over a specific ColumnFamily with a modified ReadOptions
     fn iter_opt(&self, col: Col, mode: IteratorMode, readopts: &ReadOptions) -> Result<DBIter>;
 }