Fix documentation for operators

* Avoid using 'returns changes' in docs as operators don't really
  return changes.
* Update doc for has:a_depends-on to not explain how depends-on
  plugin works

Change-Id: I3ca671a0b61c70ade0e3b63aea703de34d98ce5a

src/main/resources/Documentation/change-search-operators.md

diff --git a/src/main/resources/Documentation/change-search-operators.md b/src/main/resources/Documentation/change-search-operators.md
index 0885ac0..dc7585d 100644
--- a/src/main/resources/Documentation/change-search-operators.md
+++ b/src/main/resources/Documentation/change-search-operators.md
@@ -3,13 +3,13 @@
 
 **in_@PLUGIN@:<change>**
 
-: Returns "Depends-on" change dependencies specified in the comments of the provided change.
+: Changes that are listed as "Depends-on" change dependencies defined in the comments of the provided change.
 
 **has:a_@PLUGIN@**
 
-: Returns changes that have "Depends-on" change dependencies defined in their comments (operator does not return changes with an empty "Depends-on").
+: Changes that have at least one "Depends-on" change dependencies defined in their comments.
 
-**Operational Notes**:
+### Operational Notes:
 
 To use any operator of @PLUGIN@ plugin, change operator aliasing is needed since query parser
 cannot parse dash(-) in an operator.