non-bracket outer framing

[Felix-Kettnaker]

⚠️ disclaimer: FYI: code for this PR is entirely written by AI 🤖.

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support non_bracket nodes without a closing delimiter

What

Adds an opt-in non_bracket_node.outer_framing option (default true). Setting it to false stops a non_bracket node's format range from climbing to its parent's sibling when the node itself has no sibling on that side.

Why

search.range frames a non_bracket node by its surrounding siblings, falling back to the parent's sibling when the node has none:

local first = n:prev_sibling() or n:parent():prev_sibling()
local last  = n:next_sibling() or n:parent():next_sibling()

This is correct for languages whose blocks have an explicit closing delimiter token (e.g. Lua's then ... end, where the delimiter is a sibling). But indentation-based languages have no closing token (Python, GDScript, CoffeeScript, …). A block that is the last child of its parent then has no next_sibling, so the fallback grabs the following statement — the join range extends over it and swallows it. This currently makes it impossible to support split/join of :-introduced indented bodies.

Change

local climb = type(non_bracket_node) ~= 'table'
  or non_bracket_node.outer_framing ~= false

local function get_framing_for_non_bracket(n)
  local first = n:prev_sibling()
  local last = n:next_sibling()
  if climb then
    first = first or n:parent():prev_sibling()
    last = last or n:parent():next_sibling()
  end
  return first, last
end

With outer_framing = false, a missing side uses the node's own range instead of the parent's sibling.

Backward compatibility

Purely additive and opt-in — outer_framing defaults to true, so framing is byte-for-byte unchanged for every existing preset. Verified against an existing non_bracket language (Lua, round-trips with a following statement intact) and bracket presets (Python lists/dicts).

Example

A non_bracket block preset with outer_framing = false on Python's block:

Before (join swallows the next statement):

if cond: do_x()return

After:

if cond: do_x()
return

Notes

Language-independent — this is the missing piece for split/join of indentation-delimited blocks in general. A companion GDScript preset PR uses it to toggle one-line if/for/while/function bodies, but the flag is useful to any such language preset.

Tests

The flag needs a configured language to exercise through the test harness; its behavior is covered by a later GDScript preset modification PR (which needs the original GDScript template first), which uses outer_framing = false for statement bodies. I can also fold a test in here (e.g. demonstrating it on Python's block) if preferred.