[gtk/css-text-transform] docs: Add text-transform CSS property

[Matthias Clasen <matthiasc src gnome org>]

commit fb4dd8fb6297befa005b3fe63f6f78b92f9364e3
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Aug 20 23:50:53 2021 -0400

    docs: Add text-transform CSS property

 docs/reference/gtk/css-properties.md | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/docs/reference/gtk/css-properties.md b/docs/reference/gtk/css-properties.md
index 357fd33c19..af8771dc06 100644
--- a/docs/reference/gtk/css-properties.md
+++ b/docs/reference/gtk/css-properties.md
@@ -162,6 +162,7 @@ done with
 |caret-color|[CSS Basic User Interface Level 3](https://www.w3.org/TR/css3-ui/#caret-color) | CSS allows an 
auto value |
 |-gtk-secondary-caret-color|[Color](https://www.w3.org/TR/css-color-3/#valuea-def-color) | used for the 
secondary caret in bidirectional text |
 |letter-spacing| [CSS Text Level 3](https://www.w3.org/TR/css3-text/#letter-spacing) | |
+|text-transform| [CSS Text Level 3](https://www.w3.org/TR/css-text-3/#text-transform-property) | CSS allows 
full-width and full-size-kana |
 |text-decoration-line| [CSS Text Decoration Level 
3](https://www.w3.org/TR/css-text-decor-3/#text-decoration-line-property) | |
 |text-decoration-color| [CSS Text Decoration Level 
3](https://www.w3.org/TR/css-text-decor-3/#text-decoration-color-property) | |
 |text-decoration-style| [CSS Text Decoration Level 
3](https://www.w3.org/TR/css-text-decor-3/#text-decoration-style-property) | CSS allows dashed and dotted |