Fix/improve handling of forward declarations in nimsuggest (#20493)

* Fix/improve handling of forward declarations in nimsuggest

- ideUse now works fine when invoked on the implementation
- implemented ideDeclaration to make cover lsp feature textDocument/declaration
- fixed performance issue related to deduplicating symbols. Now the
deduplication happens after the symbols are filtered. As a alternative we might
change the way cached symbols are stored(e. g. use set).
- I also fixed the way globalSymbols work. Now it will sort the responses based
on the match location to make sure that the results are sorted in user friendly way.

* Update nimsuggest/nimsuggest.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

compiler/modulegraphs.nim

@@ -643,11 +643,11 @@ proc `==`*(a, b: SymInfoPair): bool =
   result = a.sym == b.sym and a.info.exactEquals(b.info)
 
 proc fileSymbols*(graph: ModuleGraph, fileIdx: FileIndex): seq[SymInfoPair] =
-  result = graph.suggestSymbols.getOrDefault(fileIdx, @[]).deduplicate
+  result = graph.suggestSymbols.getOrDefault(fileIdx, @[])
 
 iterator suggestSymbolsIter*(g: ModuleGraph): SymInfoPair =
   for xs in g.suggestSymbols.values:
-    for x in xs.deduplicate:
+    for x in xs:
       yield x
 
 iterator suggestErrorsIter*(g: ModuleGraph): Suggest =

compiler/options.nim

@@ -192,7 +192,7 @@ type
   IdeCmd* = enum
     ideNone, ideSug, ideCon, ideDef, ideUse, ideDus, ideChk, ideChkFile, ideMod,
     ideHighlight, ideOutline, ideKnown, ideMsg, ideProject, ideGlobalSymbols,
-    ideRecompile, ideChanged, ideType
+    ideRecompile, ideChanged, ideType, ideDeclaration
 
   Feature* = enum  ## experimental features; DO NOT RENAME THESE!
     implicitDeref,
@@ -1026,6 +1026,7 @@ proc `$`*(c: IdeCmd): string =
   of ideMsg: "msg"
   of ideProject: "project"
   of ideGlobalSymbols: "globalSymbols"
+  of ideDeclaration: "declaration"
   of ideRecompile: "recompile"
   of ideChanged: "changed"
   of ideType: "type"

compiler/suggest.nim

@@ -164,7 +164,7 @@ proc symToSuggest*(g: ModuleGraph; s: PSym, isLocal: bool, section: IdeCmd, info
     result.tokenLen = 0
   else:
     let infox =
-      if useSuppliedInfo or section in {ideUse, ideHighlight, ideOutline}:
+      if useSuppliedInfo or section in {ideUse, ideHighlight, ideOutline, ideDeclaration}:
         info
       else:
         s.info