Split text-underline-offset from text-underline-position (web-platform-dx#2652)

These properties are related, but they can be used individually.
text-underline-position is significantly older in some browser. Usage is
also quite different:
https://chromestatus.com/metrics/css/timeline/popularity/405
https://chromestatus.com/metrics/css/timeline/popularity/661

The motivation for this is mapping the above use counters to counters
for the web-features entries. They are technically easy to measure as
one, but doing so seems unhelpful.

Co-authored-by: James Stuckey Weber <[email protected]>

Author: foolip

features/text-underline-offset.yml

@@ -0,0 +1,10 @@
+name: text-underline-offset
+description: "The `text-underline-offset` CSS property shifts underlines on text from the initial position by a given distance. The initial position is affected by the `text-underline-position` property."
+spec: https://drafts.csswg.org/css-text-decor-4/#underline-offset
+group: text
+status:
+  compute_from: css.properties.text-underline-offset
+compat_features:
+  - css.properties.text-underline-offset
+  - css.properties.text-underline-offset.auto
+  - css.properties.text-underline-offset.percentage

features/text-underline-offset.yml.dist

@@ -0,0 +1,42 @@
+# Generated from: text-underline-offset.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+status:
+  baseline: high
+  baseline_low_date: 2020-11-19
+  baseline_high_date: 2023-05-19
+  support:
+    chrome: "87"
+    chrome_android: "87"
+    edge: "87"
+    firefox: "70"
+    firefox_android: "79"
+    safari: "12.1"
+    safari_ios: "12.2"
+compat_features:
+  # ⬇️ Same status as overall feature ⬇️
+  # baseline: high
+  # baseline_low_date: 2020-11-19
+  # baseline_high_date: 2023-05-19
+  # support:
+  #   chrome: "87"
+  #   chrome_android: "87"
+  #   edge: "87"
+  #   firefox: "70"
+  #   firefox_android: "79"
+  #   safari: "12.1"
+  #   safari_ios: "12.2"
+  - css.properties.text-underline-offset
+  - css.properties.text-underline-offset.auto
+
+  # baseline: low
+  # baseline_low_date: 2024-12-11
+  # support:
+  #   chrome: "87"
+  #   chrome_android: "87"
+  #   edge: "87"
+  #   firefox: "74"
+  #   firefox_android: "79"
+  #   safari: "18.2"
+  #   safari_ios: "18.2"
+  - css.properties.text-underline-offset.percentage

features/text-underline-position.yml

@@ -1,13 +1,10 @@
-name: Text underline position
-description: "The `text-underline-position` and `text-underline-offset` CSS properties set the position and distance from initial position of text underlines on text with `text-decoration: underline`."
-spec: https://drafts.csswg.org/css-text-decor-4/#line-decoration
+name: text-underline-position
+description: "The `text-underline-position` CSS property sets the position of underlines on text. For example, `text-underline-position: under` places the underline below the text, avoiding crossing descenders. The underline may be further adjusted by the `text-underline-offset` property."
+spec: https://drafts.csswg.org/css-text-decor-4/#text-underline-position-property
 group: text
 status:
-  compute_from: css.properties.text-underline-offset
+  compute_from: css.properties.text-underline-position
 compat_features:
-  - css.properties.text-underline-offset
-  - css.properties.text-underline-offset.auto
-  - css.properties.text-underline-offset.percentage
   - css.properties.text-underline-position
   - css.properties.text-underline-position.from-font
   - css.properties.text-underline-position.left

features/text-underline-position.yml.dist

@@ -3,17 +3,18 @@
 
 status:
   baseline: high
-  baseline_low_date: 2020-11-19
-  baseline_high_date: 2023-05-19
+  baseline_low_date: 2020-07-28
+  baseline_high_date: 2023-01-28
   support:
-    chrome: "87"
-    chrome_android: "87"
-    edge: "87"
-    firefox: "70"
+    chrome: "33"
+    chrome_android: "33"
+    edge: "12"
+    firefox: "74"
     firefox_android: "79"
     safari: "12.1"
     safari_ios: "12.2"
 compat_features:
+  # ⬇️ Same status as overall feature ⬇️
   # baseline: high
   # baseline_low_date: 2020-07-28
   # baseline_high_date: 2023-01-28
@@ -40,21 +41,6 @@ compat_features:
   #   safari_ios: "12.2"
   - css.properties.text-underline-position.under
 
-  # ⬇️ Same status as overall feature ⬇️
-  # baseline: high
-  # baseline_low_date: 2020-11-19
-  # baseline_high_date: 2023-05-19
-  # support:
-  #   chrome: "87"
-  #   chrome_android: "87"
-  #   edge: "87"
-  #   firefox: "70"
-  #   firefox_android: "79"
-  #   safari: "12.1"
-  #   safari_ios: "12.2"
-  - css.properties.text-underline-offset
-  - css.properties.text-underline-offset.auto
-
   # baseline: high
   # baseline_low_date: 2020-11-19
   # baseline_high_date: 2023-05-19
@@ -80,15 +66,3 @@ compat_features:
   #   safari_ios: "18.2"
   - css.properties.text-underline-position.left
   - css.properties.text-underline-position.right
-
-  # baseline: low
-  # baseline_low_date: 2024-12-11
-  # support:
-  #   chrome: "87"
-  #   chrome_android: "87"
-  #   edge: "87"
-  #   firefox: "74"
-  #   firefox_android: "79"
-  #   safari: "18.2"
-  #   safari_ios: "18.2"
-  - css.properties.text-underline-offset.percentage