[scraperhelper] Update metric units (open-telemetry#10656)

#### Description
`1` isn't an informative unit for metrics, this clarifies the unit.

#### Link to tracking issue
Fixes
open-telemetry#10649

.chloggen/scraperhelper_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: scraperhelper
+
+# 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: [10649]
+
+# (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: []

receiver/scraperhelper/documentation.md

@@ -12,12 +12,12 @@ Number of metric points that were unable to be scraped.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {datapoints} | Sum | Int | true |
 
 ### otelcol_scraper_scraped_metric_points
 
 Number of metric points successfully scraped.
 
 | Unit | Metric Type | Value Type | Monotonic |
 | ---- | ----------- | ---------- | --------- |
-| 1 | Sum | Int | true |
+| {datapoints} | Sum | Int | true |

receiver/scraperhelper/metadata.yaml

@@ -12,15 +12,15 @@ telemetry:
     scraper_scraped_metric_points:
       enabled: true
       description: Number of metric points successfully scraped.
-      unit: "1"
+      unit: "{datapoints}"
       sum:
         value_type: int
         monotonic: true
 
     scraper_errored_metric_points:
       enabled: true
       description: Number of metric points that were unable to be scraped.
-      unit: "1"
+      unit: "{datapoints}"
       sum:
         value_type: int
         monotonic: true