Update broken external links

Update external links according to information returned in the
redirect.

doc/administration/logs.md

@@ -352,7 +352,7 @@ only. For example:
 ## `audit_json.log`
 
 NOTE: **Note:**
-Most log entries only exist in [GitLab Starter](https://about.gitlab.com/pricing), however a few exist in GitLab Core.
+Most log entries only exist in [GitLab Starter](https://about.gitlab.com/pricing/), however a few exist in GitLab Core.
 
 This file lives in `/var/log/gitlab/gitlab-rails/audit_json.log` for
 Omnibus GitLab packages or in `/home/git/gitlab/log/audit_json.log` for

doc/administration/monitoring/prometheus/pgbouncer_exporter.md

@@ -10,7 +10,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 Available since [Omnibus GitLab 11.0](https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/2493).
 For installations from source you'll have to install and configure it yourself.
 
-The [PgBouncer exporter](https://github.com/stanhu/pgbouncer_exporter) allows you to measure various PgBouncer metrics.
+The [PgBouncer exporter](https://github.com/prometheus-community/pgbouncer_exporter) allows you to measure various PgBouncer metrics.
 
 To enable the PgBouncer exporter:
 

doc/development/documentation/index.md

@@ -59,7 +59,7 @@ However, anyone can contribute [documentation improvements](improvement-workflow
 ## Markdown and styles
 
 [GitLab docs](https://gitlab.com/gitlab-org/gitlab-docs) uses [GitLab Kramdown](https://gitlab.com/gitlab-org/gitlab_kramdown)
-as its Markdown rendering engine. See the [GitLab Markdown Guide](https://about.gitlab.com/handbook/engineering/ux/technical-writing/markdown-guide/) for a complete Kramdown reference.
+as its Markdown rendering engine. See the [GitLab Markdown Guide](https://about.gitlab.com/handbook/markdown-guide/) for a complete Kramdown reference.
 
 Adhere to the [Documentation Style Guide](styleguide.md). If a style standard is missing, you are welcome to suggest one via a merge request.
 
@@ -512,7 +512,7 @@ This list does not limit what other linters you can add to your local documentat
 [markdownlint](https://github.com/DavidAnson/markdownlint) checks that Markdown
 syntax follows [certain rules](https://github.com/DavidAnson/markdownlint/blob/master/doc/Rules.md#rules),
 and is used by the [`docs-lint` test](#testing) with a [configuration file](#markdownlint-configuration).
-Our [Documentation Style Guide](styleguide.md#markdown) and [Markdown Guide](https://about.gitlab.com/handbook/engineering/ux/technical-writing/markdown-guide/)
+Our [Documentation Style Guide](styleguide.md#markdown) and [Markdown Guide](https://about.gitlab.com/handbook/markdown-guide/)
 elaborate on which choices must be made when selecting Markdown syntax for GitLab
 documentation. This tool helps catch deviations from those guidelines.
 

doc/user/project/integrations/prometheus_units.md

@@ -19,7 +19,7 @@ Currently, your [internationalization and localization options](https://en.wikip
 
 For generic or default data, numbers are formatted according to the current locale in [engineering notation](https://en.wikipedia.org/wiki/Engineering_notation).
 
-While an [engineering notation exists for the web](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NumberFormat), GitLab uses a version based off the [scientific notation](https://en.wikipedia.org/wiki/Scientific_notation). GitLab formatting acts in accordance with SI prefixes. For example, using GitLab notation, `1500.00` becomes `1.5k` instead of `1.5E3`. Keep this distinction in mind when using the engineering notation for your metrics.
+While an [engineering notation exists for the web](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat), GitLab uses a version based off the [scientific notation](https://en.wikipedia.org/wiki/Scientific_notation). GitLab formatting acts in accordance with SI prefixes. For example, using GitLab notation, `1500.00` becomes `1.5k` instead of `1.5E3`. Keep this distinction in mind when using the engineering notation for your metrics.
 
 Formats: `engineering`