DOCS-964 Fix agg operator return value type to boolean instead of integer

Author: kay-kim

source/reference/aggregation/gt.txt

@@ -6,7 +6,7 @@ $gt (aggregation)
 
 .. expression:: $gt
 
-   Takes two values in an array and returns an integer. The returned
+   Takes two values in an array and returns an boolean. The returned
    value is:
 
    - ``true`` when the first value is *greater than* the second value.

source/reference/aggregation/gte.txt

@@ -6,7 +6,7 @@ $gte (aggregation)
 
 .. expression:: $gte
 
-   Takes two values in an array and returns an integer. The returned
+   Takes two values in an array and returns an boolean. The returned
    value is:
 
    - ``true`` when the first value is *greater than or equal* to the

source/reference/aggregation/lt.txt

@@ -6,7 +6,7 @@ $lt (aggregation)
 
 .. expression:: $lt
 
-   Takes two values in an array and returns an integer. The returned
+   Takes two values in an array and returns an boolean. The returned
    value is:
 
    - ``true`` when the first value is *less than* the second value.

source/reference/aggregation/lte.txt

@@ -6,7 +6,7 @@ $lte (aggregation)
 
 .. expression:: $lte
 
-   Takes two values in an array and returns an integer. The returned
+   Takes two values in an array and returns an boolean. The returned
    value is:
 
    - ``true`` when the first value is *less than or equal to* the

source/reference/aggregation/ne.txt

@@ -6,7 +6,7 @@ $ne (aggregation)
 
 .. expression:: $ne
 
-   Takes two values in an array returns an integer. The returned value
+   Takes two values in an array returns an boolean. The returned value
    is:
 
    - ``true`` when the values are **not equivalent**.