Support using soft keyword

Author: nicolasstucki

src/typescript/Scala.tmLanguage.ts

@@ -168,6 +168,9 @@ export const scalaTmLanguage: TmLanguage = {
         {
           include: '#keywords'
         },
+        {
+          include: '#using'
+        },
         {
           include: '#constants'
         },
@@ -320,6 +323,18 @@ export const scalaTmLanguage: TmLanguage = {
         }
       ]
     },
+    'using': {
+      patterns: [
+        {
+          match: `\\(\\s*(using)`,
+          captures: {
+            '1': {
+              name: 'keyword.declaration.scala'
+            }
+          }
+        }
+      ]
+    },
     'string-interpolation': {
       patterns: [
         {

tests/unit/using.test.scala

@@ -0,0 +1,23 @@
+// SYNTAX TEST "source.scala"
+
+def f(using x: Int): Unit = ()
+//    ^^^^^ keyword.declaration.scala
+
+  f(using 2)
+//  ^^^^^ keyword.declaration.scala
+//        ^ constant.numeric.scala
+
+class A(using x: Int)
+//      ^^^^^ keyword.declaration.scala
+
+new A(using 3)
+//    ^^^^^ keyword.declaration.scala
+//          ^ constant.numeric.scala
+
+given [T](using x: Ord[T], using: Int) as Ord[List[T]]
+//        ^^^^^ keyword.declaration.scala
+//              ^ variable.parameter.scala
+//                         ^^^^^ variable.parameter.scala
+
+given [T](using Ord[T]) as Ord[List[T]]
+//        ^^^^^ keyword.declaration.scala