Document how to compare text with Argos (#206)

Author: gregberge

docs/learn/guides/visual-coverage/compare-non-image-files.mdx

@@ -0,0 +1,53 @@
+---
+slug: /compare-non-image-files
+sidebar_label: Non-image comparisons
+description: Compare text-based artifacts in Argos by uploading them with the CLI.
+---
+
+import { RunPkgCommand } from "@site/src/partials";
+
+# Compare non-image files
+
+Argos can compare more than screenshots. With the CLI, you can upload text-based artifacts such as API snapshots, generated HTML, Markdown files, CSS output, JavaScript bundles, XML documents, YAML files, or JSON fixtures and review their changes in Argos.
+
+![Compare non-image files in Argos](json-comparison.png)
+
+## Upload non-image files
+
+Use the `-f` or `--files` option to tell the CLI which files to upload:
+
+<RunPkgCommand
+  command={
+    'argos upload -f "**/*.{txt,json,yaml,yml,xml,html,md,css,js}" ./snapshots'
+  }
+/>
+
+The `-f` option replaces the default screenshot glob. If you want to upload screenshots and non-image files in the same build, include both patterns:
+
+<RunPkgCommand
+  command={[
+    'argos upload -f "**/*.{png,jpg,jpeg}" "**/*.{txt,json,yaml,yml,xml,html,md,css,js}" ./snapshots',
+  ]}
+/>
+
+Use stable file names and paths so Argos can match each uploaded file with its baseline on future builds.
+
+## Supported content types
+
+Argos currently supports these non-image content types:
+
+- `text/plain`
+- `application/json`
+- `application/yaml`
+- `text/yaml`
+- `application/xml`
+- `text/xml`
+- `text/html`
+- `text/markdown`
+- `text/css`
+- `application/javascript`
+- `text/javascript`
+
+## Framework support
+
+Non-image comparisons are only supported through the CLI for now. [Contact us](mailto:contact@argos-ci.com) if you are interested in using this feature from a test framework like Vitest.

docs/learn/guides/visual-coverage/json-comparison.png

@@ -47,6 +47,10 @@ Use the `upload` command to upload screenshots stored in your `./screenshots` di
 
 <RunPkgCommand command="argos upload ./screenshots" />
 
+### Compare non-image files
+
+Use `-f` or `--files` to upload text-based artifacts such as JSON, YAML, XML, HTML, Markdown, CSS, or JavaScript files. See [Compare non-image files](/compare-non-image-files) for examples and the full list of supported content types.
+
 ### Debug mode
 
 You can enable debug mode by setting the `DEBUG` environment variable.