functions: Clarify over-time semantics

content/docs/querying/functions.md

@@ -331,8 +331,11 @@ sample value.
 The following functions allow aggregating each series of a given range vector
 over time and return an instant vector with per-series aggregation results:
 
-* `avg_over_time(range-vector)`: the average value of all points under the specified interval.
-* `min_over_time(range-vector)`: the minimum value of all points under the specified interval.
-* `max_over_time(range-vector)`: the maximum value of all points under the specified interval.
-* `sum_over_time(range-vector)`: the sum of all values under the specified interval.
-* `count_over_time(range-vector)`: the count of all values under the specified interval.
+* `avg_over_time(range-vector)`: the average value of all points in the specified interval.
+* `min_over_time(range-vector)`: the minimum value of all points in the specified interval.
+* `max_over_time(range-vector)`: the maximum value of all points in the specified interval.
+* `sum_over_time(range-vector)`: the sum of all values in the specified interval.
+* `count_over_time(range-vector)`: the count of all values in the specified interval.
+
+Note that all values in the specified interval have the same weight in the
+aggregation even if the values are not equally spaced throughout the interval.