chore: add missing docs lint and document public API

Add `#![deny(missing_docs)]` across multiple crates and fill in
documentation for all public items, including struct fields, enum
variants, trait methods, and proc macros.  Also mark two shell scripts
as executable.

2 files changed, 6 insertions, 0 deletions

diff --git a/mingling_core/src/renderer/render_result.rs b/mingling_core/src/renderer/render_result.rs
index 763f6fc..2c60fa4 100644
--- a/mingling_core/src/renderer/render_result.rs
+++ b/mingling_core/src/renderer/render_result.rs
@@ -8,6 +8,11 @@ use std::{
 #[derive(Default, Debug, PartialEq)]
 pub struct RenderResult {
     render_text: String,
+
+    /// The exit code to return from the rendering process.
+    ///
+    /// A value of `0` indicates success, while non-zero values indicate
+    /// various error conditions.
     pub exit_code: i32,
 }
 
diff --git a/mingling_core/src/renderer/structural/error.rs b/mingling_core/src/renderer/structural/error.rs
index a7fbc75..63ded81 100644
--- a/mingling_core/src/renderer/structural/error.rs
+++ b/mingling_core/src/renderer/structural/error.rs
@@ -9,6 +9,7 @@ pub struct StructuralRendererSerializeError {
 }
 
 impl StructuralRendererSerializeError {
+    /// Creates a new `StructuralRendererSerializeError` with the given error message.
     #[must_use]
     pub fn new(error: String) -> Self {
         Self { error }