fix: quickfix support for long-running providers (#41)

* fix(compiler): open quickfix in background, retain focus on source buffer

* fix(compiler): use cwindow and win_gotoid for quickfix focus management

* fix: unused var warning and update typst reload test for short format

* fix: remove testing files

spec/presets_spec.lua

@@ -50,7 +50,9 @@ describe('presets', function()
       assert.is_table(result)
       assert.are.equal('typst', result[1])
       assert.are.equal('watch', result[2])
-      assert.are.equal(ctx.file, result[3])
+      assert.are.equal('--diagnostic-format', result[3])
+      assert.are.equal('short', result[4])
+      assert.are.equal(ctx.file, result[5])
     end)
 
     it('parses errors from stderr', function()