Hints: morph hint to avoid issue

Workaround recently added hint in a related way to FL0089,
in order to avoid issue found in:
6fa06f1

Author: knocte

src/FSharpLint.Core/fsharplint.json

@@ -451,7 +451,7 @@
             "pattern: x::[] ===> [x]",
 
             "x @ [] ===> x",
-            "[x] @ y ===> x::y",
+            "(List.singleton x) @ y ===> x :: y",
 
             "List.isEmpty [] ===> true",
             "Array.isEmpty [||] ===> true",

tests/FSharpLint.Core.Tests/Rules/Hints/HintMatcher.fs

@@ -957,21 +957,10 @@ let x y =
 
     [<Test>]
     member this.``List append of singleton item can be replaced with :: operator``() =
-        let source = """[head] @ tail"""
+        let source = """(List.singleton head) @ tail"""
 
         let expected = """head :: tail"""
 
-        this.SetConfig(["[x] @ y ===> x::y"])
+        this.SetConfig(["(List.singleton x) @ y ===> x :: y"])
         this.Parse(source)
         Assert.AreEqual(expected, this.ApplyQuickFix source)
-
-    [<Test>]
-    member this.``Demonstrate issue with recently added hint``() =
-        let source = """[a;b] @ tail"""
-
-        this.SetConfig(["[x] @ y ===> x::y"])
-        this.Parse(source)
-
-        // invalid!
-        Assert.AreNotEqual("a;b :: tail", this.ApplyQuickFix source)
-