add "some warnings detected" to ParseError printing when all problems are warnings

src/parser_api.jl

@@ -16,13 +16,16 @@ function ParseError(stream::ParseStream; incomplete_tag=:none, kws...)
 end
 
 function Base.showerror(io::IO, err::ParseError)
-    println(io, "ParseError:")
     # Only show the first parse error for now - later errors are often
     # misleading due to the way recovery works
     i = findfirst(is_error, err.diagnostics)
     if isnothing(i)
         i = lastindex(err.diagnostics)
+        level_info = " some warnings detected:"
+    else
+        level_info = ""
     end
+    println(io, "ParseError:", level_info)
     show_diagnostics(io, err.diagnostics[1:i], err.source)
 end
 

test/parser_api.jl

@@ -163,7 +163,7 @@ end
     catch exc
         @test exc isa JuliaSyntax.ParseError
         @test sprint(showerror, exc) == """
-            ParseError:
+            ParseError: some warnings detected:
             # Warning @ somefile.jl:1:2
             @(a)
             #└─┘ ── parenthesizing macro names is unnecessary"""