Add explanation of codes

Author: OliviaYtterbrink

modules/ROOT/pages/errors/gql-errors/51N52.adoc

@@ -5,6 +5,10 @@
 == Status description
 error: system configuration or operation exception - number of primaries out of range. Cannot `{ <<action>> }` database topology.  Number of primaries `{ <<count>> }` needs to be at least 1 and may not exceed `{ <<upper>> }`.
 
+== Explanation
+
+This error occurs when trying to create or alter a database while providing a topology with primary count outside the supported range.
+
 ifndef::backend-pdf[]
 [discrete.glossary]
 == Glossary

modules/ROOT/pages/errors/gql-errors/51N53.adoc

@@ -5,6 +5,10 @@
 == Status description
 error: system configuration or operation exception - number of secondaries out of range. Cannot `{ <<action>> }` database topology. Number of secondaries `{ <<count>> }` needs to be at least 0 and may not exceed `{ <<upper>> }`.
 
+== Explanation
+
+This error occurs when trying to create or alter a database while providing a topology with secondary count outside the supported range.
+
 ifndef::backend-pdf[]
 [discrete.glossary]
 == Glossary