Add 'style guide' to Vale substitution rules

doc/.vale/gitlab/Substitutions.yml

@@ -20,5 +20,6 @@ swap:
   rspec: RSpec
   self hosted: self-managed
   self-hosted: self-managed
+  styleguide: style guide
   x509: X.509
   yaml: YAML

doc/api/graphql/getting_started.md

@@ -2,7 +2,7 @@
 
 This guide demonstrates basic usage of GitLab's GraphQL API.
 
-See the [GraphQL API StyleGuide](../../development/api_graphql_styleguide.md) for implementation details
+See the [GraphQL API style guide](../../development/api_graphql_styleguide.md) for implementation details
 aimed at developers who wish to work on developing the API itself.
 
 ## Running examples

doc/development/README.md

@@ -57,8 +57,8 @@ Complementary reads:
 - [GitLab utilities](utilities.md)
 - [Issuable-like Rails models](issuable-like-models.md)
 - [Logging](logging.md)
-- [API styleguide](api_styleguide.md) for contributing to the API
-- [GraphQL API styleguide](api_graphql_styleguide.md) for contributing to the [GraphQL API](../api/graphql/index.md)
+- [API style guide](api_styleguide.md) for contributing to the API
+- [GraphQL API style guide](api_graphql_styleguide.md) for contributing to the [GraphQL API](../api/graphql/index.md)
 - [Sidekiq guidelines](sidekiq_style_guide.md) for working with Sidekiq workers
 - [Working with Gitaly](gitaly.md)
 - [Manage feature flags](feature_flags/index.md)
@@ -177,7 +177,7 @@ Complementary reads:
 ## Documentation guides
 
 - [Writing documentation](documentation/index.md)
-- [Documentation styleguide](documentation/styleguide.md)
+- [Documentation style guide](documentation/styleguide.md)
 - [Markdown](../user/markdown.md)
 
 ## Internationalization (i18n) guides

doc/development/api_graphql_styleguide.md

-# GraphQL API
+# GraphQL API style guide
 
-This document outlines the styleguide for GitLab's [GraphQL API](../api/graphql/index.md).
+This document outlines the style guide for GitLab's [GraphQL API](../api/graphql/index.md).
 
 ## How GitLab implements GraphQL
 
@@ -365,7 +365,7 @@ field :token, GraphQL::STRING_TYPE, null: true,
 The original `description:` of the field should be maintained, and should
 _not_ be updated to mention the deprecation.
 
-### Deprecation reason styleguide
+### Deprecation reason style guide
 
 Where the reason for deprecation is due to the field being replaced
 with another field, the `reason` must be:
@@ -446,7 +446,7 @@ Descriptions of fields and arguments are viewable to users through:
 - The [GraphiQL explorer](#graphiql).
 - The [static GraphQL API reference](../api/graphql/#reference).
 
-### Description styleguide
+### Description style guide
 
 To ensure consistency, the following should be followed whenever adding or updating
 descriptions:

doc/development/api_styleguide.md

-# API styleguide
+# API style guide
 
-This styleguide recommends best practices for API development.
+This style guide recommends best practices for API development.
 
 ## Instance variables
 

doc/development/contributing/style_guides.md

@@ -53,7 +53,7 @@ should enable all RuboCop rules to avoid style-related
 discussions/nitpicking/back-and-forth in reviews.
 
 Additionally, we have a dedicated
-[newlines styleguide](../newlines_styleguide.md), as well as dedicated
+[newlines style guide](../newlines_styleguide.md), as well as dedicated
 [test-specific style guides and best practices](../testing_guide/index.md).
 
 ## Database migrations

doc/development/newlines_styleguide.md

-# Newlines styleguide
+# Newlines style guide
 
 This style guide recommends best practices for newlines in Ruby code.
 

doc/development/testing_guide/index.md

@@ -4,7 +4,7 @@ This document describes various guidelines and best practices for automated
 testing of the GitLab project.
 
 It is meant to be an _extension_ of the [thoughtbot testing
-styleguide](https://github.com/thoughtbot/guides/tree/master/style/testing). If
+style guide](https://github.com/thoughtbot/guides/tree/master/style/testing). If
 this guide defines a rule that contradicts the thoughtbot guide, this guide
 takes precedence. Some guidelines may be repeated verbatim to stress their
 importance.