New syntax for cursorless overrides

[pokey]

The problem

Our current override csvs are missing a couple pieces of functionality:

• Context-specific definitions / overrides, eg only active when in Python file
• Extra information on members, such as we would want for Add arguments to cursorless_vscode_command #453, and potentially for snippets, though for snippets we might want the information VSCode-side

The solution

We'd like to switch to a syntax like the following:

language: python
-
hello world: bar
whatever: false {}
whatever:
    false
    {}
export {}
import
empty map: {}
empty quotes: ""
-: setSelection

Notice the following:

• Spoken form, then colon, then value
• Can have a json object at the end
• These are actually defining captures, not lists, because lists can't have any info other than a string. There will also be a list, but it won't have the extra info
• If no colon, spoken form equals value
• above the - is just a talon context
• the filename will be foo.bar.capture, where foo will be the name of the list and the capture. Might tweak the extension (.list? .cursorless-list?)
• can break into multiple lines, as long as they're indented
• starting spoken form with a - removes it

Alternatives considered

yaml

scope:
    language: python
list:
    hello world: bar

toml

[scope]
language = "python"

[list.my_list]
hello world = "bar"

toml with talon context header

language: python
-
[my_list]
hello world = "bar"

[my_list.whatever now]
value = 

[pokey]

It's worth considering if we can apply the new Talon list file syntax

[josharian]

I believe the new Talon list file syntax hits most of the reqs, except:

• Can have a json object at the end -- but maybe this can be handled during the translation from list to capture
• can break into multiple lines, as long as they're indented -- maybe not critical?
• starting spoken form with a - removes it -- maybe by accident?