visual studio is opening unity script as miscellaneous file code example
Example: unity visual studio miscellaneous file
//1 - backup your project
//2 - quit both VS and Unity
//3 - remove all generated sln/csproj
//4 - remove the .vs folder
//5 - remove the Library folder
//6 - re-open the project with Unity
//7 - In Unity, use Assets/Open C# Project