doc: Update doc/metrics.md

Co-authored-by: Daniel Dyla <[email protected]>

doc/metrics.md

@@ -23,7 +23,7 @@ _Metrics API Reference: <https://open-telemetry.github.io/opentelemetry-js-api/c
   - [Exporting measurements to Opentelemetry Protocol](#exporting-measurements-to-opentelemetry-protocol)
 
 ## Getting Started
-In thie page, you'll leaarn how to setup Opentelemetry and metrics from an HTTP server with Fastify. If you're not using Fastify, that's fine -- this guide will also work with Express, etc.
+In this page, you'll learn how to setup OpenTelemetry JS to export metrics from an HTTP server with Fastify. If you're not using Fastify, the concepts in this guide will still apply.
 
 ### Installation
 To begin, set up an environment in a new directory: