Fix doc comment example of FromSql implementation.
Fix doc comment example of FromSql implementation.

gwenn/rusqlite,xinghun92/rusqlite,jgallagher/rusqlite,xinghun92/rusqlite,mikelodder7/rusqlcipher,jgallagher/rusqlite,mikelodder7/rusqlcipher,mikelodder7/rusqlcipher,jgallagher/rusqlite,xinghun92/rusqlite,gwenn/rusqlite,gwenn/rusqlite