Fix capitalization of headings and subheadings

Bring the capitalization of menus and page headings in line with
each other.

doc/operations/metrics/dashboards/variables.md

@@ -4,9 +4,9 @@ group: APM
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Using Variables **(CORE)**
+# Using variables **(CORE)**
 
-## Query Variables
+## Query variables
 
 Variables can be specified using double curly braces, such as `"{{ci_environment_slug}}"` ([added](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/20793) in GitLab 12.7).
 
@@ -41,7 +41,7 @@ For example, if the dashboard time range is set to 8 hours, the value of
 
 [Variables can be defined](../../../operations/metrics/dashboards/yaml.md#templating-templating-properties) in a custom dashboard YAML file.
 
-## Query Variables from URL
+## Query variables from URL
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/214500) in GitLab 13.0.
 

doc/operations/metrics/index.md

@@ -4,7 +4,7 @@ group: APM
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Monitor metrics for your CI/CD environment **(CORE)**
+# Metrics dashboard for your CI/CD environment **(CORE)**
 
 After [configuring Prometheus for a cluster](../../user/project/integrations/prometheus.md),
 GitLab attempts to retrieve performance metrics for any [environment](../../ci/environments/index.md) with

doc/user/incident_management/index.md

@@ -4,7 +4,7 @@ group: Health
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Incident Management
+# Incident management
 
 GitLab offers solutions for handling incidents in your applications and services,
 such as setting up Prometheus alerts, displaying metrics, and sending notifications.

doc/user/project/integrations/prometheus_library/cloudwatch.md

@@ -4,7 +4,7 @@ group: APM
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Monitoring AWS Resources
+# Monitoring AWS resources
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/12621) in GitLab 9.4
 

doc/user/project/operations/alert_management.md

@@ -4,7 +4,7 @@ group: Health
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Alert Management
+# Alert management
 
 > [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/2877) in GitLab 13.0.
 

doc/user/project/operations/dashboard_settings.md

@@ -4,7 +4,7 @@ group: APM
 info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
 ---
 
-# Metrics dashboard settings
+# Dashboard settings
 
 You can configure your [Monitoring dashboard](../integrations/prometheus.md) to
 display the time zone of your choice, and the links of your choice.

doc/user/project/operations/error_tracking.md

@@ -8,7 +8,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 > [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/169) in GitLab 11.8.
 
-Error tracking allows developers to easily discover and view the errors that their application may be generating. By surfacing error information where the code is being developed, efficiency and awareness can be increased.
+Error Tracking allows developers to easily discover and view the errors that their application may be generating. By surfacing error information where the code is being developed, efficiency and awareness can be increased.
 
 ## Sentry error tracking