Make `_block` a visible scope

[ChrHorn]

Most languages make their blocks inside functions, classes, etc visible.

• end: Lua, Ruby (this was changed recently issue/PR)
• indent: Python
• {}: C++, Rust, ...

This added visible scope would make targeting the inside/body of a function much easier. Textobjekt queries that do this are currently very cumbersome to do.

The other advantage is tree-sitter based expanding/shrinking selection. Currently it is
expression -> whole function
with this change it would be
expression -> function body -> whole function
It would be much easier to select these code blocks without selecting the surrounding syntax.

I think just changing everything to block should be fine. The exception would be the top scope. Here we already have source_file, so an additional scope is not needed.

[Ronan Arraes Jardim Chagas]

This modification will be very welcome for Emacs. I am trying to design a Julia major mode (https://github.com/ronisbr/julia-ts-mode) and without this feature the automatic indentation will not work very well. For example, if we type:

function test(a)
end

And then press enter after ), the cursor will start at the beginning of the line because there is no node inside the function body. Hence, we cannot apply an indentation rule in Emacs at least.