chore: dialog t-shirt sizing

- adds deprecation notice for --small/--medium/--large class names,
in favor of the t-shirt sizing class names.
- create changeset

.changeset/nasty-pillows-wonder.md

@@ -0,0 +1,7 @@
+---
+"@spectrum-css/dialog": patch
+---
+
+Dialog t-shirt sizes
+
+Adds support for t-shirt sizing class names to dialog CSS. `@deprecated` comments were added to communicate that the old class names (`--small`, `--medium`, and `--large`) will be removed in S2.

components/dialog/index.css

@@ -43,24 +43,28 @@
 	/* Allow 100% width, taking into account padding */
 	box-sizing: border-box;
 
-	/* Be no bigger than max-width,  but also be 90% if the viewport is smaller than max-width */
-	inline-size: fit-content;
+	/* Be no bigger than max-width, but also be 90% if the viewport is smaller than max-width */
+	inline-size: var(--mod-dialog-confirm-medium-width, var(--spectrum-dialog-confirm-medium-width));
 	min-inline-size: var(--mod-dialog-min-inline-size, var(--spectrum-dialog-min-inline-size));
 	max-inline-size: 100%;
 
 	max-block-size: inherit;
 
 	outline: none;
 }
-
+/* @deprecated .spectrum-Dialog--small */
+.spectrum-Dialog--sizeS,
 .spectrum-Dialog--small {
 	inline-size: var(--mod-dialog-confirm-small-width, var(--spectrum-dialog-confirm-small-width));
 }
 
+/* @deprecated .spectrum-Dialog--medium */
 .spectrum-Dialog--medium {
 	inline-size: var(--mod-dialog-confirm-medium-width, var(--spectrum-dialog-confirm-medium-width));
 }
 
+/* @deprecated .spectrum-Dialog--large */
+.spectrum-Dialog--sizeL,
 .spectrum-Dialog--large {
 	inline-size: var(--mod-dialog-confirm-large-width, var(--spectrum-dialog-confirm-large-width));
 }