diagnostic: Use resolve_scopes soft_scope kwarg directly

JuliaLang/julia#61476 allows us to remove the `insert_softscope_marker`
workaround that inserted `K"softscope"` nodes into the AST and pass
the `soft_scope` keword arg directly instead.

Author: aviatesk

Project.toml

@@ -27,8 +27,8 @@ TOML = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
 [sources]
 Compiler = {rev = "avi/julia-JETLS-Compiler-head-2026-03-15", subdir = "Compiler", url = "https://github.com/JuliaLang/julia"}
 JET = {rev = "476bd141", url = "https://github.com/aviatesk/JET.jl"}
-JuliaLowering = {rev = "avi/julia-JETLS-JSJL-head-2026-03-28", subdir = "JuliaLowering", url = "https://github.com/JuliaLang/julia"}
-JuliaSyntax = {rev = "avi/julia-JETLS-JSJL-head-2026-03-28", subdir = "JuliaSyntax", url = "https://github.com/JuliaLang/julia"}
+JuliaLowering = {rev = "avi/JL-fix-soft-scope", subdir = "JuliaLowering", url = "https://github.com/JuliaLang/julia"}
+JuliaSyntax = {rev = "avi/JL-fix-soft-scope", subdir = "JuliaSyntax", url = "https://github.com/JuliaLang/julia"}
 LSP = {path = "LSP"}
 
 [compat]

src/utils/binding.jl

@@ -29,14 +29,6 @@ function is_relevant(ctx3::JL.AbstractLoweringContext,
          || cursor > start)
 end
 
-function insert_softscope_marker(st1::JS.SyntaxTree)
-    g = JS.syntax_graph(st1)
-    marker = JS.newleaf(g, st1, JS.K"softscope")
-    children = JS.SyntaxList(g)
-    push!(children, marker, st1)
-    return JS.newnode(g, st1, JS.K"block", children)
-end
-
 """
     jl_lower_for_scope_resolution(
             mod::Module, st0::JS.SyntaxTree;
@@ -91,10 +83,7 @@ function _jl_lower_for_scope_resolution(
         soft_scope::Bool = false,
     )
     ctx2, st2 = JL.expand_forms_2(ctx1, st1)
-    if soft_scope
-        st2 = insert_softscope_marker(st2)
-    end
-    ctx3, st3 = JL.resolve_scopes(ctx2, st2)
+    ctx3, st3 = JL.resolve_scopes(ctx2, st2; soft_scope)
     convert_closures || return (; st0, st1, st2, st3, ctx3)
     ctx4, st4 = JL.convert_closures(ctx3, st3)
     return (; st0, st1, st2, st3, st4, ctx3, ctx4)