(feat) highlight units in strings (#1316)

Author: Monkatraz

packages/svelte-vscode/syntaxes/svelte.tmLanguage.src.yaml

@@ -364,9 +364,12 @@ repository:
     # No quotes - just an interpolation expression.
     - include: '#interpolation'
     # Units, meaning digit characters and an optional unit string. e.g. `15px`
-    - match: ([0-9._]+[\w]{,4})(?=\s|/?>)
-      name: constant.numeric.decimal.svelte
-      patterns: [ include: '#interpolation' ]
+    - match: (?:(['"])([0-9._]+[\w%]{,4})(\1))|(?:([0-9._]+[\w%]{,4})(?=\s|/?>))
+      captures:
+        1: { name: punctuation.definition.string.begin.svelte }
+        2: { name: constant.numeric.decimal.svelte }
+        3: { name: punctuation.definition.string.end.svelte }
+        4: { name: constant.numeric.decimal.svelte }
     # Unquoted strings.
     - match: ([^\s"'=<>`/]|/(?!>))+
       name: string.unquoted.svelte