[chore] remove dev warning (open-telemetry#37160)

Remove a development warning in the README which is no longer true as
the receiver has been in alpha for a little while.

---------

Co-authored-by: Alex Boten <223565+codeboten@users.noreply.github.com>

receiver/ntpreceiver/README.md

@@ -12,8 +12,6 @@
 [contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
 <!-- end autogenerated section -->
 
-> :construction: This receiver is in development. Configuration fields and metric data model are subject to change.
-
 ## Purpose
 
 This receiver periodically retrieves the clock offset from a NTP server.
@@ -26,7 +24,7 @@ This receiver periodically retrieves the clock offset from a NTP server.
 
 - `initial_delay` (default = `1s`): defines how long this receiver waits before starting.
 
-- `metrics` (default: see DefaultMetricsSettings [here])(./internal/metadata/generated_metrics.go): Allows enabling and disabling specific metrics from being collected in this receiver.
+- `metrics` (default: see DefaultMetricsSettings [here](./internal/metadata/generated_metrics.go)): Allows enabling and disabling specific metrics from being collected in this receiver.
 
 ### Example Configuration