Backport "Fix: -no-link-warnings does not work" to LTS (#19029)

Backports #17028 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

Author: Kordyjan

project/ScaladocGeneration.scala

@@ -97,6 +97,10 @@ object ScaladocGeneration {
     def key: String = "-no-link-warnings"
   }
 
+  case class NoLinkAssetWarnings(value: Boolean) extends Arg[Boolean] {
+    def key: String = "-no-link-asset-warnings"
+  }
+
   case class VersionsDictionaryUrl(value: String) extends Arg[String] {
     def key: String = "-versions-dictionary-url"
   }

scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala

@@ -39,6 +39,7 @@ object Scaladoc:
     documentSyntheticTypes: Boolean = false,
     snippetCompiler: List[String] = Nil,
     noLinkWarnings: Boolean = false,
+    noLinkAssetWarnings: Boolean = false,
     versionsDictionaryUrl: Option[String] = None,
     generateInkuire : Boolean = false,
     apiSubdirectory : Boolean = false,
@@ -221,6 +222,7 @@ object Scaladoc:
         YdocumentSyntheticTypes.get,
         snippetCompiler.get,
         noLinkWarnings.get,
+        noLinkAssetWarnings.get,
         versionsDictionaryUrl.nonDefault,
         generateInkuire.get,
         apiSubdirectory.get,

scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala

@@ -87,6 +87,12 @@ class ScaladocSettings extends SettingGroup with AllScalaSettings:
     false
   )
 
+  val noLinkAssetWarnings: Setting[Boolean] = BooleanSetting(
+    "-no-link-asset-warnings",
+    "Avoid warnings for incorrect links of assets like images, static pages, etc.",
+    false
+  )
+
   val versionsDictionaryUrl: Setting[String] = StringSetting(
     "-versions-dictionary-url",
     "versions dictionary url",

scaladoc/src/dotty/tools/scaladoc/renderers/SiteRenderer.scala

@@ -63,7 +63,10 @@ trait SiteRenderer(using DocContext) extends Locations:
         .orElse(asStaticSite)
         .orElse(asAsset)
         .getOrElse {
-          report.warn(s"Unable to resolve link '$str'", content.template.templateFile.file)
+          if (!summon[DocContext].args.noLinkAssetWarnings){
+            val msg = s"Unable to resolve link '$str'"
+            report.warn(msg, content.template.templateFile.file)
+          }
           str
         }