Remove inline from Contents extension methods to fix ScalaDoc NPE

ScalaDoc 3.7.4 crashes with NullPointerException in
ScalaSignatureProvider.methodSignature when generating docs for
inline extension methods on an opaque type (Contents). The crash
is deterministic on Linux x86_64 (CI) but not on macOS ARM64.

Removing inline preserves identical behavior — these are trivial
one-line delegations that the compiler optimizes regardless.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: respencer-ncl

language/shared/src/main/scala/com/ossuminc/riddl/language/Contents.scala

@@ -29,7 +29,7 @@ object Contents:
     mutable.ArrayBuffer.unapplySeq[T](contents)
 
   extension [CV <: RiddlValue](container: Contents[CV])
-    inline def apply(n: Int): CV = container.apply(n)
+    def apply(n: Int): CV = container.apply(n)
 end Contents
 
 extension [CV <: RiddlValue](sequence: Seq[CV])
@@ -40,35 +40,35 @@ extension [CV <: RiddlValue](sequence: Seq[CV])
     )
 
 extension [CV <: RiddlValue](container: Contents[CV])
-  inline def length: Int = container.length
-  inline def size: Int = container.length
-  inline def head: CV = container(0)
-  inline def indexOf[B >: CV](elem: B): Int = container.indexOf[B](elem, 0)
-  inline def splitAt(n: Int): (Contents[CV], Contents[CV]) = container.splitAt(n)
-  inline def indices: Range = Range(0, container.length)
-  inline def foreach[T](f: CV => T): Unit = container.foreach(f)
-  inline def forall(p: CV => Boolean): Boolean = container.forall(p)
-  inline def update(index: Int, elem: CV): Unit = container.update(index, elem)
-  inline def foldLeft[B](z: B)(op: (B, CV) => B): B = container.foldLeft[B](z)(op)
-  inline def isEmpty: Boolean = container.isEmpty
-  inline def nonEmpty: Boolean = !isEmpty
-  inline def mapValue[B <: RiddlValue](f: CV => B): Contents[B] = container.map[B](f)
-  inline def flatMap[B <: RiddlValue](f: CV => IterableOnce[B]): Contents[B] =
+  def length: Int = container.length
+  def size: Int = container.length
+  def head: CV = container(0)
+  def indexOf[B >: CV](elem: B): Int = container.indexOf[B](elem, 0)
+  def splitAt(n: Int): (Contents[CV], Contents[CV]) = container.splitAt(n)
+  def indices: Range = Range(0, container.length)
+  def foreach[T](f: CV => T): Unit = container.foreach(f)
+  def forall(p: CV => Boolean): Boolean = container.forall(p)
+  def update(index: Int, elem: CV): Unit = container.update(index, elem)
+  def foldLeft[B](z: B)(op: (B, CV) => B): B = container.foldLeft[B](z)(op)
+  def isEmpty: Boolean = container.isEmpty
+  def nonEmpty: Boolean = !isEmpty
+  def mapValue[B <: RiddlValue](f: CV => B): Contents[B] = container.map[B](f)
+  def flatMap[B <: RiddlValue](f: CV => IterableOnce[B]): Contents[B] =
     container.flatMap[B](f)
-  inline def startsWith[B >: CV](that: IterableOnce[B], offset: Int = 0): Boolean =
+  def startsWith[B >: CV](that: IterableOnce[B], offset: Int = 0): Boolean =
     container.startsWith[B](that)
   def toSet[B >: CV <: RiddlValue]: immutable.Set[B] = immutable.Set.from(container)
   def toSeq: immutable.Seq[CV] = container.toSeq
   def toIterator: Iterator[CV] = container.toIterator
-  inline def dropRight(howMany: Int): Contents[CV] = container.dropRight(howMany)
-  inline def drop(howMany: Int): Contents[CV] = container.drop(howMany)
-  inline def clear(): Unit = container.clear()
-  inline def remove(index: Int): CV = container.remove(index)
-  inline def append(elem: CV): Unit = container.append(elem)
-  inline def prepend(elem: CV): Unit = container.prepend(elem)
-  inline def +=(elem: CV): Contents[CV] = { container.addOne(elem); container }
-  inline def ++=(suffix: IterableOnce[CV]): Contents[CV] = { container.addAll(suffix); container }
-  inline def ++(suffix: IterableOnce[CV]): Contents[CV] =
+  def dropRight(howMany: Int): Contents[CV] = container.dropRight(howMany)
+  def drop(howMany: Int): Contents[CV] = container.drop(howMany)
+  def clear(): Unit = container.clear()
+  def remove(index: Int): CV = container.remove(index)
+  def append(elem: CV): Unit = container.append(elem)
+  def prepend(elem: CV): Unit = container.prepend(elem)
+  def +=(elem: CV): Contents[CV] = { container.addOne(elem); container }
+  def ++=(suffix: IterableOnce[CV]): Contents[CV] = { container.addAll(suffix); container }
+  def ++(suffix: IterableOnce[CV]): Contents[CV] =
     container.concat[CV](suffix).asInstanceOf[Contents[CV]]
   private def identified: Contents[CV] = container.filter(_.isIdentified)
   def filter[T <: RiddlValue: ClassTag]: Seq[T] =