Fix broken doc links (#12615)

docs/getting-started/config-env.md

@@ -36,4 +36,4 @@ warning message in your logs when you try to access that variable
 Only certain features require "real" keys, so you may be able to add them as you
 work on different areas of the application.
 
-[backend_guide]: /docs/backend
+[backend_guide]: /backend

docs/installation/linux.md

@@ -46,8 +46,8 @@ Forem requires PostgreSQL version 11 or higher.
    username you are currently logged in as.
 
 There are more than one ways to setup PostgreSQL. For additional configuration,
-check out our [PostgreSQL setup guide](/docs/installation/postgresql) or the
-official [PostgreSQL](https://www.postgresql.org/) site for further information.
+check out our [PostgreSQL setup guide](/installation/postgresql) or the official
+[PostgreSQL](https://www.postgresql.org/) site for further information.
 
 ### ImageMagick
 
@@ -93,9 +93,8 @@ NOTE: Make sure to download **the OSS version**, `elasticsearch-oss`.
      use and provides a fake default for any missing keys.
    - If you use a remote computer as dev env, you need to set `APP_DOMAIN`
      variable to the remote computer's domain name.
-   - The [backend guide](/docs/backend) will show you how to get free API keys
-     for additional services that may be required to run certain parts of the
-     app.
+   - The [backend guide](/backend) will show you how to get free API keys for
+     additional services that may be required to run certain parts of the app.
    - For any key that you wish to enter/replace:
 
      1. Create `.env` by copying from the provided template (i.e. with bash:

docs/installation/windows.md

@@ -151,7 +151,7 @@ password for PostgreSQL:
    PostgreSQL by executing the command `\quit`.
 
 For additional configuration options, check our
-[PostgreSQL setup guide](/docs/installation/postgresql).
+[PostgreSQL setup guide](/installation/postgresql).
 
 ### ImageMagick
 
@@ -260,9 +260,8 @@ To install Elasticsearch perform the following steps:
      use and provides a fake default for any missing keys.
    - If you use a remote computer as dev env, you need to set `APP_DOMAIN`
      variable to the remote computer's domain name.
-   - The [backend guide](/docs/backend) will show you how to get free API keys
-     for additional services that may be required to run certain parts of the
-     app.
+   - The [backend guide](/backend) will show you how to get free API keys for
+     additional services that may be required to run certain parts of the app.
    - For any key that you wish to enter/replace:
 
      1. Create `.env` by copying from the provided template (ie. with bash:

docs/readme.md

@@ -55,8 +55,8 @@ for those changes to take effect.
 If you're looking for more information on contributing, check out the
 [Contributing guide][contributing].
 
-[installation]: /docs/installation/
-[architecture]: /docs/technical-overview/architecture/
-[contributing]: /docs/contributing/
+[installation]: /installation/
+[architecture]: /technical-overview/architecture/
+[contributing]: /contributing/
 [docs]: https://github.com/forem/forem/tree/master/docs/
 [gitdocs]: https://www.npmjs.com/package/gitdocs/