Add link to "submit a PR" to ecosystem pages (open-telemetry#5571)

Author: chalin

content/en/ecosystem/distributions.md

@@ -24,7 +24,7 @@ is provided as a convenience for the community. {{% /alert %}}
 
 ## How to add your distribution {#how-to-add}
 
-To have your distribution listed, submit a PR with an entry added to the
+To have your distribution listed, [submit a PR] with an entry added to the
 [distributions list](https://github.com/open-telemetry/opentelemetry.io/tree/main/data/ecosystem/distributions.yaml).
 The entry should include the following:
 
@@ -46,3 +46,5 @@ The entry should include the following:
   to end users, see [Vendors](/ecosystem/vendors).
 
 {{% /alert %}}
+
+[submit a PR]: /docs/contributing/pull-requests/

content/en/ecosystem/integrations.md

@@ -44,8 +44,8 @@ have a CNCF logo beside their name.
 
 ## How to add your integration {#how-to-add}
 
-To have your library, service, or app listed, submit a PR with an entry added to
-the [registry](/ecosystem/registry/adding). The entry should include the
+To have your library, service, or app listed, [submit a PR] with an entry added
+to the [registry](/ecosystem/registry/adding). The entry should include the
 following:
 
 - Link to the main page of your library, service, or app
@@ -65,3 +65,5 @@ If you provide a solution that consumes OpenTelemetry to offer observability to
 end users, see [Vendors](/ecosystem/vendors).
 
 {{% /alert %}}
+
+[submit a PR]: /docs/contributing/pull-requests/

content/en/ecosystem/vendors.md

@@ -21,7 +21,7 @@ source product for their customers.
 
 ## Add your organization
 
-To have your organization listed, submit a PR with an entry added to the
+To have your organization listed, [submit a PR] with an entry added to the
 [vendors list](https://github.com/open-telemetry/opentelemetry.io/tree/main/data/ecosystem/vendors.yaml).
 The entry should include the following:
 
@@ -42,3 +42,5 @@ you do not provide any kind of services around OpenTelemetry, see
 
 If you provide a library, service, or app that is made observable through
 OpenTelemetry, see [Integrations](/ecosystem/integrations).
+
+[submit a PR]: /docs/contributing/pull-requests/