Update vscode-textmate module to 5.x

[glennsarti]

VSCode now uses the vscode-textmate module of 5.x which had breaking API
changes. However there are some issues:

• The new version uses a promise instead of sync calls. This can be overcome but it's annoying.

• Most importantly, the inspect script fails because the required object properties no longer exist in 4.0+ of the module. This means a debug tool is not possible when developing the textmate file.

Need to raise a feature request on that node module.