fix(docs): typo in OTLP histograms to Prometheus (open-telemetry#4182)

Author: javiergarea

specification/compatibility/prometheus_and_openmetrics.md

@@ -325,7 +325,7 @@ An [OpenTelemetry Histogram](../metrics/data-model.md#histogram) with a cumulati
 
 - A single `{name}_count` metric denoting the count field of the histogram. All attributes of the histogram point are converted to Prometheus labels.
 - `{name}_sum` metric denoting the sum field of the histogram, reported only if the sum is positive and monotonic. The sum is positive and monotonic when all buckets are positive. All attributes of the histogram point are converted to Prometheus labels.
-- A series of `{name}_bucket` metric points that contain all attributes of the histogram point recorded as labels.  Additionally, a label, denoted as `le` is added denoting the bucket boundary. The label's value is the stringified floating point value of bucket boundaries, ordered from lowest to highest. The value of each point is the sum of the count of all histogram buckets up the the boundary reported in the `le` label. These points will include a single exemplar that falls within `le` label and no other `le` labelled point.  The final bucket metric MUST have an `+Inf` threshold.
+- A series of `{name}_bucket` metric points that contain all attributes of the histogram point recorded as labels.  Additionally, a label, denoted as `le` is added denoting the bucket boundary. The label's value is the stringified floating point value of bucket boundaries, ordered from lowest to highest. The value of each point is the sum of the count of all histogram buckets up to the boundary reported in the `le` label. These points will include a single exemplar that falls within `le` label and no other `le` labelled point.  The final bucket metric MUST have an `+Inf` threshold.
 - Histograms with `StartTimeUnixNano` set should export the `{name}_created` metric as well.
 
 OpenTelemetry Histograms with Delta aggregation temporality SHOULD be aggregated into a Cumulative aggregation temporality and follow the logic above, or MUST be dropped.