Minimal implementation of wing fmt for whitespace cleanup

[MarkMcCulloh]

Use Case

An opinioned formatting tool helps keep code beautiful and frees PRs from formatting nitpicks.
We have #475 but it focuses on enforcing certain stylistic things present in the spec. It would be useful to focus on a minimal but useful whitespace formatter.

Proposed Solution

wing fmt defaults to all wing files in the current directory, can otherwise provide a path to do the following:

• Remove trailing whitespace per line
• Remove extra whitespace between between most tokens on the same line
  • let x = 2; becomes let x = 2;
• Add single whitespace between most tokens
  • let x=2; becomes let x = 2;
  • func(a,b) should become func(a, b)
• Indenting for { at end of line and unindenting for }
  • Tabs?

Additionally, we should expose this formatter in the vscode extension (see here)

Implementation Notes

Ideally this is something that can be implemented solely with the tree-sitter tree to keep it simple.

Component

No response

Community Notes

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[eladb]

Would it make sense that by default wing compile will also format?

[MarkMcCulloh]

It would be a pretty bold choice, not sure I've seen any compilers/tools mutate user-created sources automatically during compilation.
We could start with a --fix flag, which could also do other things like inserting semicolons.

[eladb]

Sounds good for the CLI, but can we make this the default behavior in VSCode? Format on save?