feat(core)!: replace RenderResult with buffered output model

Remove `Deref<Target=str>` and `render_text:String` in favor of
`render_buffer:Vec<(String, RenderResultMode)>` and an
`immediate_output`
flag. Add `RenderResultMode` enum, `r_eprint!`/`r_eprintln!` macros, and
new buffer manipulation methods (`append_to_buffer`, `eprint`, etc.).
Update `Display` to trim output and remove trailing newline. Migrate all
callers and tests away from `Deref` usage.

1 files changed, 3 insertions, 2 deletions

diff --git a/mingling_core/tests/test-structural-renderer/tests/integration.rs b/mingling_core/tests/test-structural-renderer/tests/integration.rs
index 3c3c6db..0bcf53a 100644
--- a/mingling_core/tests/test-structural-renderer/tests/integration.rs
+++ b/mingling_core/tests/test-structural-renderer/tests/integration.rs
@@ -1,4 +1,4 @@
-use mingling::{StructuralRenderer, StructuralRendererSetting, RenderResult, StructuralData};
+use mingling::{RenderResult, StructuralData, StructuralRenderer, StructuralRendererSetting};
 use serde::Serialize;
 
 #[derive(Debug, Clone, PartialEq, Serialize, StructuralData)]
@@ -17,7 +17,8 @@ fn test_data() -> TestData {
 #[test]
 fn test_render_disable() {
     let mut r = RenderResult::default();
-    let result = StructuralRenderer::render(&test_data(), &StructuralRendererSetting::Disable, &mut r);
+    let result =
+        StructuralRenderer::render(&test_data(), &StructuralRendererSetting::Disable, &mut r);
     assert!(result.is_ok());
     assert!(r.is_empty());
 }