Determine indent level from more modes

Namely `graphql-mode`, `html-mode`, `ruby-mode`, `ruby-ts-mode`,
`svelte-mode`, and `yaml-mode`.

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog].
 
 ## Unreleased
+### Enhancements
+* Indent level is now determined for `graphql-mode`, `html-mode`, `ruby-mode`,
+  `ruby-ts-mode`, `svelte-mode`, and `yaml-mode` ([#258]).
+
 ### Formatters
 * [`js-beautify`](https://github.com/beautify-web/js-beautify) for
   [JavaScript](https://www.javascript.com/),
@@ -15,6 +19,7 @@ The format is based on [Keep a Changelog].
   ([#263]).
 
 [#229]: https://github.com/radian-software/apheleia/pull/229
+[#258]: https://github.com/radian-software/apheleia/pull/258
 [#263]: https://github.com/radian-software/apheleia/pull/263
 
 ## 4.0 (released 2023-11-23)

apheleia-utils.el

@@ -37,6 +37,8 @@ always returns nil to defer to the formatter."
             (cl-case major-mode
               (css-mode 'css-indent-offset)
               (css-ts-mode 'css-indent-offset)
+              (graphql-mode 'graphql-indent-level)
+              (html-mode 'sgml-basic-offset)
               (js-jsx-mode 'js-indent-level)
               (js-ts-mode 'js-indent-level)
               (js-mode 'js-indent-level)
@@ -47,11 +49,15 @@ always returns nil to defer to the formatter."
               (json-ts-mode 'json-ts-mode-indent-offset)
               (nxml-mode 'nxml-child-indent)
               (robot-mode 'robot-mode-basic-offset)
+              (ruby-mode 'ruby-indent-level)
+              (ruby-ts-mode 'ruby-indent-level)
               (scss-mode 'css-indent-offset)
+              (svelte-mode 'svelte-basic-offset)
               (web-mode 'web-mode-indent-style)
               (tsx-ts-mode 'typescript-ts-mode-indent-offset)
               (typescript-mode 'typescript-indent-level)
-              (typescript-ts-mode 'typescript-ts-mode-indent-offset))))
+              (typescript-ts-mode 'typescript-ts-mode-indent-offset)
+              (yaml-mode 'yaml-indent-offset))))
 
     (when-let ((indent (and indent-var
                             (boundp indent-var)