add protos for != queries (#1856)

Author: Brian Chen

firebase-firestore/src/proto/google/firestore/v1/query.proto

@@ -85,32 +85,74 @@ message StructuredQuery {
       // Unspecified. This value must not be used.
       OPERATOR_UNSPECIFIED = 0;
 
-      // Less than. Requires that the field come first in `order_by`.
+      // The given `field` is less than the given `value`.
+      //
+      // Requires:
+      //
+      // * That `field` come first in `order_by`.
       LESS_THAN = 1;
 
-      // Less than or equal. Requires that the field come first in `order_by`.
+      // The given `field` is less than or equal to the given `value`.
+      //
+      // Requires:
+      //
+      // * That `field` come first in `order_by`.
       LESS_THAN_OR_EQUAL = 2;
 
-      // Greater than. Requires that the field come first in `order_by`.
+      // The given `field` is greater than the given `value`.
+      //
+      // Requires:
+      //
+      // * That `field` come first in `order_by`.
       GREATER_THAN = 3;
 
-      // Greater than or equal. Requires that the field come first in
-      // `order_by`.
+      // The given `field` is greater than or equal to the given `value`.
+      //
+      // Requires:
+      //
+      // * That `field` come first in `order_by`.
       GREATER_THAN_OR_EQUAL = 4;
 
-      // Equal.
+      // The given `field` is equal to the given `value`..
       EQUAL = 5;
 
-      // Contains. Requires that the field is an array.
+      // The given `field` is not equal to the given `value`.
+      //
+      // Requires:
+      //
+      // * No other `NOT_EQUAL`, `NOT_IN`, `IS_NOT_NULL`, or `IS_NOT_NAN`.
+      // * That `field` comes first in the `order_by`.
+      NOT_EQUAL = 6;
+
+      // The given `field` is an array that contains the given `value`.
       ARRAY_CONTAINS = 7;
 
-      // In. Requires that `value` is a non-empty ArrayValue with at most 10
-      // values.
+      // The given `field` is equal to at least one value in the given array.
+      //
+      // Requires:
+      //
+      // * That `value` is a non-empty `ArrayValue` with at most 10 values.
+      // * No other `IN` or `ARRAY_CONTAINS_ANY`. (-- or `NOT_IN` --)
       IN = 8;
 
-      // Contains any. Requires that the field is an array and
-      // `value` is a non-empty ArrayValue with at most 10 values.
+      // The given `field` is an array that contains any of the values in the
+      // given array.
+      //
+      // Requires:
+      //
+      // * That `value` is a non-empty `ArrayValue` with at most 10 values.
+      // * No other `IN` or `ARRAY_CONTAINS_ANY`. (-- or `NOT_IN` --)
       ARRAY_CONTAINS_ANY = 9;
+
+      // The value of the `field` is not in the given array.
+      //
+      // Requires:
+      //
+      // * That `value` is a non-empty `ArrayValue` with at most 10 values.
+      // * No other `IN`, `ARRAY_CONTAINS_ANY`, `NOT_IN`, `NOT_EQUAL`,
+      //   `IS_NOT_NULL`, or `IS_NOT_NAN`.
+      // * That `field` comes first in the `order_by`.
+      NOT_IN = 10;
     }
 
     // The field to filter by.
@@ -127,14 +169,30 @@ message StructuredQuery {
   message UnaryFilter {
     // A unary operator.
     enum Operator {
-      // Unspecified. This value must not be used.
-      OPERATOR_UNSPECIFIED = 0;
-
-      // Test if a field is equal to NaN.
-      IS_NAN = 2;
-
-      // Test if an exprestion evaluates to Null.
-      IS_NULL = 3;
+     // Unspecified. This value must not be used.
+     OPERATOR_UNSPECIFIED = 0;
+
+     // The given `field` is equal to `NaN`.
+     IS_NAN = 2;
+
+     // The given `field` is equal to `NULL`.
+     IS_NULL = 3;
+
+     // The given `field` is not equal to `NaN`.
+     //
+     // Requires:
+     //
+     // * No other `NOT_EQUAL`, `NOT_IN`, `IS_NOT_NULL`, or `IS_NOT_NAN`.
+     // * That `field` comes first in the `order_by`.
+     IS_NOT_NAN = 4;
+
+     // The given `field` is not equal to `NULL`.
+     //
+     // Requires:
+     //
+     // * A single `NOT_EQUAL`, `NOT_IN`, `IS_NOT_NULL`, or `IS_NOT_NAN`.
+     // * That `field` comes first in the `order_by`.
+     IS_NOT_NULL = 5;
     }
 
     // The unary operator to apply.