Add new semantic token modifiers in gopls 0.17

[xzbdmw]

Is your feature request related to a problem? Please describe.
https://github.com/golang/tools/blob/master/gopls/doc/release/v0.17.0.md#semantic-token-modifiers-of-top-level-constructor-of-types

Describe the solution you'd like
Add those as default capabilities for vscode

interface, struct, signature, pointer, array, map, slice, chan, string, number, bool, and invalid

[findleyr]

CC @h9jiang

[hyangah]

@h9jiang fyi https://github.com/rust-lang/rust-analyzer/blob/d3bb15ecec7c1386767c45776fab497e8a22a30f/editors/code/package.json#L3060

[h9jiang]

A CL will be sent out for review so the user will be able to customize what kind to modifiers and types they want gopls to report. The result will looks like screenshot above.

[xzbdmw]

customize what kind to modifiers and types they want gopls to report

I feel this is not needed, because vscode users need to define the color of those "not in spec" modifiers, otherwise there are no visual differences.