Standardize spelling of dropdown

In discussions in #docs-style today, we determined that we were
inconsistent in spelling 'dropdown':

- dropdown
- drop down
- drop-down

This commit standardizes on 'dropdown,' but cannot yet put in a
test for it.

doc/administration/audit_events.md

@@ -107,7 +107,7 @@ recorded:
 - Started/stopped user impersonation
 
 It is possible to filter particular actions by choosing an audit data type from
-the filter drop-down. You can further filter by specific group, project or user
+the filter dropdown box. You can further filter by specific group, project or user
 (for authentication events).
 
 ![audit log](img/audit_log.png)

doc/administration/monitoring/prometheus/index.md

@@ -245,7 +245,7 @@ To add a Prometheus dashboard for a single server GitLab setup:
 
 1. Create a new data source in Grafana.
 1. Name your data source i.e GitLab.
-1. Select `Prometheus` in the type drop down.
+1. Select `Prometheus` in the type dropdown box.
 1. Add your Prometheus listen address as the URL and set access to `Browser`.
 1. Set the HTTP method to `GET`.
 1. Save & Test your configuration to verify that it works.

doc/ci/enable_or_disable_ci.md

@@ -44,7 +44,7 @@ To enable or disable GitLab CI/CD Pipelines in your project:
 
 - **Private**: Only project members can access pipelines.
 - **Internal** or **Public**: Pipelines can be set to either **Only Project Members**
-  or **Everyone With Access** via the drop-down box.
+  or **Everyone With Access** via the dropdown box.
 
 Press **Save changes** for the settings to take effect.
 

doc/install/aws/index.md

@@ -244,7 +244,7 @@ Once the database is created, connect to your new RDS instance to verify access
 and to install a required extension.
 
 You can find the host or endpoint by selecting the instance you just created and
-after the details drop down you'll find it labeled as 'Endpoint'. Do not to
+after the details dropdown menu you'll find it labeled as 'Endpoint'. Do not to
 include the colon and port number:
 
 ```sh

doc/install/azure/index.md

@@ -226,7 +226,7 @@ connections:
 ![Azure - Add inbound security rules - HTTP](img/azure-add-inbound-sec-rule-http.png)
 
 1. Enter **"HTTP"** in the `Name` field
-1. Select **HTTP** from the options in the `Service` drop-down
+1. Select **HTTP** from the options in the `Service` dropdown list
 1. Make sure the `Action` is set to **Allow**
 1. Click **"OK"**
 
@@ -238,7 +238,7 @@ accept [SSH] connections:
 ![Azure - Add inbound security rules - SSH](img/azure-add-inbound-sec-rule-ssh.png)
 
 1. Enter **"SSH"** in the `Name` field
-1. Select **SSH** from the options in the `Service` drop-down
+1. Select **SSH** from the options in the `Service` dropdown list
 1. Make sure the `Action` is set to **Allow**
 1. Click **"OK"**