[exporterhelper] Update metric units (open-telemetry#10655)

#### Description
Updated the metric units for metrics in the `exporterhelper`. As
described in the issue, `1` isn't an informative unit to use, so this
should hopefully clarify metrics for users.

#### Link to tracking issue
Fixes
open-telemetry#10648

---------

Co-authored-by: Alex Boten <[email protected]>

.chloggen/exporterhelper_metric_units.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Update units for internal telemetry
+
+# One or more tracking issues or pull requests related to the change
+issues: [10648]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

exporter/exporterhelper/documentation.md

@@ -12,84 +12,84 @@ Number of log records failed to be added to the sending queue.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {records} | Sum | Int | true |
 
 ### otelcol_exporter_enqueue_failed_metric_points
 
 Number of metric points failed to be added to the sending queue.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {datapoints} | Sum | Int | true |
 
 ### otelcol_exporter_enqueue_failed_spans
 
 Number of spans failed to be added to the sending queue.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {spans} | Sum | Int | true |
 
 ### otelcol_exporter_queue_capacity
 
 Fixed capacity of the retry queue (in batches)
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+| {batches} | Gauge | Int |
 
 ### otelcol_exporter_queue_size
 
 Current size of the retry queue (in batches)
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+| {batches} | Gauge | Int |
 
 ### otelcol_exporter_send_failed_log_records
 
 Number of log records in failed attempts to send to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {records} | Sum | Int | true |
 
 ### otelcol_exporter_send_failed_metric_points
 
 Number of metric points in failed attempts to send to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {datapoints} | Sum | Int | true |
 
 ### otelcol_exporter_send_failed_spans
 
 Number of spans in failed attempts to send to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {spans} | Sum | Int | true |
 
 ### otelcol_exporter_sent_log_records
 
 Number of log record successfully sent to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {records} | Sum | Int | true |
 
 ### otelcol_exporter_sent_metric_points
 
 Number of metric points successfully sent to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {datapoints} | Sum | Int | true |
 
 ### otelcol_exporter_sent_spans
 
 Number of spans successfully sent to destination.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {spans} | Sum | Int | true |

exporter/exporterhelper/metadata.yaml

@@ -12,79 +12,79 @@ telemetry:
     exporter_sent_spans:
       enabled: true
       description: Number of spans successfully sent to destination.
-      unit: "1"
+      unit: "{spans}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_send_failed_spans:
       enabled: true
       description: Number of spans in failed attempts to send to destination.
-      unit: "1"
+      unit: "{spans}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_enqueue_failed_spans:
       enabled: true
       description: Number of spans failed to be added to the sending queue.
-      unit: "1"
+      unit: "{spans}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_sent_metric_points:
       enabled: true
       description: Number of metric points successfully sent to destination.
-      unit: "1"
+      unit: "{datapoints}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_send_failed_metric_points:
       enabled: true
       description: Number of metric points in failed attempts to send to destination.
-      unit: "1"
+      unit: "{datapoints}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_enqueue_failed_metric_points:
       enabled: true
       description: Number of metric points failed to be added to the sending queue.
-      unit: "1"
+      unit: "{datapoints}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_sent_log_records:
       enabled: true
       description: Number of log record successfully sent to destination.
-      unit: "1"
+      unit: "{records}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_send_failed_log_records:
       enabled: true
       description: Number of log records in failed attempts to send to destination.
-      unit: "1"
+      unit: "{records}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_enqueue_failed_log_records:
       enabled: true
       description: Number of log records failed to be added to the sending queue.
-      unit: "1"
+      unit: "{records}"
       sum:
         value_type: int
         monotonic: true
 
     exporter_queue_size:
       enabled: true
       description: Current size of the retry queue (in batches)
-      unit: "1"
+      unit: "{batches}"
       optional: true
       gauge:
         value_type: int
@@ -93,7 +93,7 @@ telemetry:
     exporter_queue_capacity:
       enabled: true
       description: Fixed capacity of the retry queue (in batches)
-      unit: "1"
+      unit: "{batches}"
       optional: true
       gauge:
         value_type: int