Update UnrealEngine.gitignore

[wdhongtw]

Unreal Engine supports project file generation for VSCode. Enhance Unreal ignore file for VSCode accordingly.

Reasons for making this change:

I'm an ordinary developer who is using Unreal Engine recently.

This PR makes sure that all files generated by Unreal Engine, which contains user/machine specific contents,
is ignored by this ignore template out of the box.

.vscode folder will contain a bunch of compile commands, which consist of machine specific paths.

For example, in .vscode\compileCommands_<ProjectName>.json, there will be

	{
		"file": "C:\\Users\\<username>\\Unreal Projects\\PlayUnreal\\Source\\PlayUnreal\\PlayUnreal.cpp",
		"arguments": [
			"C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Tools\\MSVC\\14.38.33130\\bin\\Hostx64\\x64\\cl.exe",
			"@C:\\Users\\<username>\\Unreal Projects\\PlayUnreal\\.vscode\\compileCommands_PlayUnreal\\PlayUnreal.1.rsp"
		],
		"directory": "C:\\Program Files\\Epic Games\\UE_5.4\\Engine\\Source"
	}

Also, in <ProjectName>.code-workspace

			{
				"name": "Launch <ProjectName> (Shipping)",
				"request": "launch",
				"program": "C:\\Users\\<username>\\Unreal Projects\\<ProjectName>\\Binaries\\Win64\\UnrealGame-Win64-Shipping.exe",
				"preLaunchTask": "<ProjectName> Win64 Shipping Build",
				"args": [
				],
				"cwd": "C:\\Program Files\\Epic Games\\UE_5.4",
				"stopAtEntry": false,
				"console": "integratedTerminal",
				"type": "cppvsdbg",
				"visualizerFile": "C:\\Program Files\\Epic Games\\UE_5.4\\Engine\\Extras\\VisualStudioDebugging\\Unreal.natvis",
				"sourceFileMap": {
					"D:\\build\\++UE5\\Sync": "C:\\Program Files\\Epic Games\\UE_5.4"
				}
			}

If we create a new C++ project from latest version of Unreal Engine (5.4), .vscode is ignored
by the generated .gitignore file. (Although *.code-workspace is still not included.)

Links to documentation supporting these rule changes:

• Setting Up Visual Studio Code for Unreal Engine | Unreal Engine 5.4 Documentation | Epic Developer Community

[wdhongtw]

As a reference, the following is the generated default .gitignore file
when creating a new Unreal Engine project throught Unreal Engine Editor (Unreal Engine Editor for Windows v5.4).

Binaries
DerivedDataCache
Intermediate
Saved
.vscode
.vs
*.VC.db
*.opensdf
*.opendb
*.sdf
*.sln
*.suo
*.xcodeproj
*.xcworkspace