[libadwaita/wip/exalm/screenshots-2: 3/17] doc: Mention -i in the tools readme

[Alexander Mikhaylenko <alexm src gnome org>]

commit 8e48ab92ddd24d3f0ecf9db9445f225f6b7c5274
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Sat Dec 18 04:42:42 2021 +0500

    doc: Mention -i in the tools readme
    
    Clarify that "image" is a placeholder.

 doc/tools/README.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/doc/tools/README.md b/doc/tools/README.md
index b795dca5..3fbef374 100644
--- a/doc/tools/README.md
+++ b/doc/tools/README.md
@@ -1,6 +1,6 @@
 # Adding a screenshot to the docs
 
-1. Create an `image.ui` file in the `data/` directory.
+1. Create an `IMAGE.ui` file in the `data/` directory.
 2. Put the widget to screenshot inside with the `widget` id. For example:
 
 ```xml
@@ -25,17 +25,17 @@ should be special-cased in `screenshot.c` based on its type.
 
 ```
 ninja doc/tools/screenshot
-./doc/tools/screenshot ../doc/images/
+./doc/tools/screenshot ../doc/images/ -i IMAGE
 ```
 
-5. The generator will create `image.png` and `image-dark.png` images. Add them
+5. The generator will create `IMAGE.png` and `IMAGE-dark.png` images. Add them
 to `libadwaita.toml.in`.
 6. Use them in the docs as follows:
 
 ```html
 <picture>
-  <source srcset="image-dark.png" media="(prefers-color-scheme: dark)">
-  <img src="image.png" alt="image">
+  <source srcset="IMAGE-dark.png" media="(prefers-color-scheme: dark)">
+  <img src="IMAGE.png" alt="IMAGE">
 </picture>
 ```