Update optimade.rst

Co-authored-by: Antanas Vaitkus <[email protected]>

Author: merkys

optimade.rst

@@ -2850,7 +2850,7 @@ bonds
   - The property SHOULD be :val:`null` for structures for which the chemical connectivity is unknown to the implementation.
   - If present, it MUST be a list of dictionaries, each of which represents a chemical bond and MUST have the following key:
 
-    - *sites*: an ordered list of 0-based indexes of the two sites that form a chemical bond.
+    - *sites*: a non-decreasing list of 0-based indexes of the two sites that form a chemical bond.
 
   - If translations are needed by at least one of the sites of a bond, the following key SHOULD be used: