IDE: Remove unused substring reference search

`Interactive.scala` offered an API to find all references to names given
substrings of the names. This feature was unused.

This worked by pretty printing the tree and
looking whether it contained the substring. This is broken, because the
substring may match parts that are not references (what if we look for
`if`?)

It's gone now.

Author: Duhemm

compiler/src/dotty/tools/dotc/interactive/Interactive.scala

@@ -265,15 +265,11 @@ object Interactive {
       namedTrees(trees, (include & Include.references) != 0, matchSymbol(_, sym, include))
 
   /** Find named trees with a non-empty position whose name contains `nameSubstring` in `trees`.
-   *
-   *  @param includeReferences  If true, include references and not just definitions
    */
-  def namedTrees(trees: List[SourceTree], includeReferences: Boolean, nameSubstring: String)
+  def namedTrees(trees: List[SourceTree], nameSubstring: String)
    (implicit ctx: Context): List[SourceTree] = {
-    val predicate: NameTree => Boolean =
-      if (includeReferences) _.show.contains(nameSubstring)
-      else _.name.toString.contains(nameSubstring)
-    namedTrees(trees, includeReferences, predicate)
+    val predicate: NameTree => Boolean = _.name.toString.contains(nameSubstring)
+    namedTrees(trees, includeReferences = false, predicate)
   }
 
   /** Find named trees with a non-empty position satisfying `treePredicate` in `trees`.

language-server/src/dotty/tools/languageserver/DottyLanguageServer.scala

@@ -428,7 +428,7 @@ class DottyLanguageServer extends LanguageServer
       implicit val ctx = driver.currentCtx
 
       val trees = driver.allTrees
-      val defs = Interactive.namedTrees(trees, includeReferences = false, nameSubstring = query)
+      val defs = Interactive.namedTrees(trees, nameSubstring = query)
       defs.flatMap(d => symbolInfo(d.tree.symbol, d.namePos, positionMapperFor(d.source)))
     }.asJava
   }