docs: migrate renderer examples to buffer macro and update docs

Update all documentation and code examples to use the new
`#[renderer(buffer)]`
pattern with `r_println!` instead of manually constructing
`RenderResult`
with `writeln!`.

1 files changed, 16 insertions, 15 deletions

diff --git a/README.md b/README.md
index cb7efb0..2c21198 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,9 @@ You can use this approach to separate computation from result rendering, like th
 
 ```rust
 // Features: ["picker"]
+use mingling::macros::buffer;
+use mingling::prelude::*;
+
 dispatcher!("calc", CMDCalculate => EntryCalculate);
 pack!(StateSumNumbers = Vec<i32>);
 pack!(ResultNumber = i32);
@@ -82,11 +85,9 @@ fn handle_state_sum_numbers(sum: StateSumNumbers) -> ResultNumber {
 }
 
 // Renderer: return the render result and let the framework handle output
-#[renderer]
-fn render_number(number: ResultNumber) -> RenderResult {
-    let mut result = RenderResult::new();
-    writeln!(result, "Number: {}", *number).ok();
-    result
+#[renderer(buffer)]
+fn render_number(number: ResultNumber) {
+    r_println!("Number: {}", *number);
 }
 ```
 
@@ -117,16 +118,16 @@ features = []
 ## Roadmap
 
 - [x] Milestone.1 "MVP" 🎉
-  - [x] [[0.1.4](https://docs.rs/mingling/0.1.4/mingling/)] [`core`] [`structural_renderer`] **Mingling** can render data into serializable formats via `--json` and `--yaml` flags
-  - [x] [[0.1.5](https://docs.rs/mingling/0.1.5/mingling/)] [`core`] [`comp`] **Mingling** can dynamically invoke itself to provide completions for shells like `bash`, `zsh`, `fish`, and `pwsh`
-  - [x] [[0.1.6](https://docs.rs/mingling/0.1.6/mingling/)] [`core`] [`comp`] **Mingling** can gather more context for smarter completions
-  - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`clap`] Provides a **Clap** compatibility layer, allowing **Mingling** to reuse its powerful parsing capabilities
-  - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`core`] **Mingling** can intercept `-h` or `--help` flags to display custom help text for each subcommand
-  - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`mling`] Provides a basic scaffolding tool (`mling`) for rapid development and debugging
-  - [x] [[0.1.8](https://docs.rs/mingling/0.1.8/mingling/)] [`core`] [`dispatch_tree`] Converts the subcommand list into a prefix tree to improve command matching speed
-  - [x] [[0.1.9](https://docs.rs/mingling/0.1.9/mingling/)] [`core`] [`dev_toolkits`] Provides debugging interfaces for developers to capture invocation information when issues arise (`InvokeStackDisplay`) (indirectly implemented via `ProgramHook`)
-  - [x] [[0.1.9](https://docs.rs/mingling/0.1.9/mingling/)] [`core`] [`repl`] Provides REPL capability (`program.exec_repl();`)
-  - [x] [[0.2.0](https://docs.rs/mingling/0.2.0/mingling/)] Complete documentation, tests, and examples
+    - [x] [[0.1.4](https://docs.rs/mingling/0.1.4/mingling/)] [`core`] [`structural_renderer`] **Mingling** can render data into serializable formats via `--json` and `--yaml` flags
+    - [x] [[0.1.5](https://docs.rs/mingling/0.1.5/mingling/)] [`core`] [`comp`] **Mingling** can dynamically invoke itself to provide completions for shells like `bash`, `zsh`, `fish`, and `pwsh`
+    - [x] [[0.1.6](https://docs.rs/mingling/0.1.6/mingling/)] [`core`] [`comp`] **Mingling** can gather more context for smarter completions
+    - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`clap`] Provides a **Clap** compatibility layer, allowing **Mingling** to reuse its powerful parsing capabilities
+    - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`core`] **Mingling** can intercept `-h` or `--help` flags to display custom help text for each subcommand
+    - [x] [[0.1.7](https://docs.rs/mingling/0.1.7/mingling/)] [`mling`] Provides a basic scaffolding tool (`mling`) for rapid development and debugging
+    - [x] [[0.1.8](https://docs.rs/mingling/0.1.8/mingling/)] [`core`] [`dispatch_tree`] Converts the subcommand list into a prefix tree to improve command matching speed
+    - [x] [[0.1.9](https://docs.rs/mingling/0.1.9/mingling/)] [`core`] [`dev_toolkits`] Provides debugging interfaces for developers to capture invocation information when issues arise (`InvokeStackDisplay`) (indirectly implemented via `ProgramHook`)
+    - [x] [[0.1.9](https://docs.rs/mingling/0.1.9/mingling/)] [`core`] [`repl`] Provides REPL capability (`program.exec_repl();`)
+    - [x] [[0.2.0](https://docs.rs/mingling/0.2.0/mingling/)] Complete documentation, tests, and examples
 - [ ] Milestone.2 "More Comfortable Dev and User Experience"
     - [ ] [`mling` / `mingling-cli`]
         - [ ] **Mingling** Linter