docs(mango): match description of `$mod` with reality
The remainder argument for the `$mod` operator can be zero, while
its documentation suggests otherwise. It actually covers a very
realistic use case where divisibility is expressed.
Neither related restrictions could be identified in the sources
[1] nor MongoDB forbids this [2]. Tests also seem to exercise this
specific case [3]. Thanks @iilyak for checking on these.
[1] https://github.com/apache/couchdb/blob/adf17140e81d0b74f2b2ecdea48fc4f702832eaf/src/mango/src/mango_selector.erl#L512:L513
[2] https://www.mongodb.com/docs/manual/reference/operator/query/mod/
[3] https://github.com/apache/couchdb/blob/0059b8f90e58e10b199a4b768a06a762d12a30d3/src/mango/test/03-operator-test.py#L58
diff --git a/src/docs/src/api/database/find.rst b/src/docs/src/api/database/find.rst
index 2ec5cc6..d1dfe6e 100644
--- a/src/docs/src/api/database/find.rst
+++ b/src/docs/src/api/database/find.rst
@@ -704,8 +704,8 @@
| | | | document. Non-array fields cannot |
| | | | match this condition. |
+---------------+-------------+------------+-----------------------------------+
-| Miscellaneous | ``$mod`` | [Divisor, | Divisor and Remainder are both |
-| | | Remainder] | positive or negative integers. |
+| Miscellaneous | ``$mod`` | [Divisor, | Divisor is a non-zero integer, |
+| | | Remainder] | Remainder is any integer. |
| | | | Non-integer values result in a |
| | | | 404. Matches documents where |
| | | | ``field % Divisor == Remainder`` |
diff --git a/src/mango/README.md b/src/mango/README.md
index 4c4bb60..9fa273b 100644
--- a/src/mango/README.md
+++ b/src/mango/README.md
@@ -302,7 +302,7 @@
Misc related operators
-* "$mod" - [Divisor, Remainder], where Divisor and Remainder are both positive integers (ie, greater than 0). Matches documents where (field % Divisor == Remainder) is true. This is false for any non-integer field
+* "$mod" - [Divisor, Remainder], where Divisor is a non-zero integer and Remainder is any integer. Matches documents where (field % Divisor == Remainder) is true. This is false for any non-integer field
* "$regex" - string, a regular expression pattern to match against the document field. Only matches when the field is a string value and matches the supplied matches
