Add templates for text markup.

default_environment/templates/html/bold.dust

@@ -1 +1,3 @@
-bold
+<b>{#.children}
+  {>object/}
+{/.children}</b>

default_environment/templates/html/code.dust

@@ -1 +1 @@
-code
+<code>{.source}</code>

default_environment/templates/html/italic.dust

@@ -1 +1,3 @@
-italic
+<i>{#.children}
+  {>object/}
+{/.children}</i>

default_environment/templates/html/plain_text.dust

@@ -1 +1 @@
-plain_text
+{.source}

default_environment/templates/html/strike_through.dust

@@ -1 +1,3 @@
-strike_through
+<del>{#.children}
+  {>object/}
+{/.children}</del>

default_environment/templates/html/underline.dust

@@ -1 +1,3 @@
-underline
+<u>{#.children}
+  {>object/}
+{/.children}</u>

default_environment/templates/html/verbatim.dust

@@ -1 +1 @@
-verbatim
+<code>{.source}</code>

src/context/plain_text.rs

@@ -9,15 +9,19 @@ use crate::intermediate::IPlainText;
 #[derive(Debug, Serialize)]
 #[serde(tag = "type")]
 #[serde(rename = "plain_text")]
-pub(crate) struct RenderPlainText {}
+pub(crate) struct RenderPlainText {
+    source: String,
+}
 
 impl RenderPlainText {
     pub(crate) fn new(
         config: &Config,
         output_directory: &Path,
         output_file: &Path,
-        heading: &IPlainText,
+        original: &IPlainText,
     ) -> Result<RenderPlainText, CustomError> {
-        Ok(RenderPlainText {})
+        Ok(RenderPlainText {
+            source: original.source.clone(),
+        })
     }
 }

src/intermediate/plain_text.rs

@@ -5,7 +5,7 @@ use super::registry::Registry;
 
 #[derive(Debug)]
 pub(crate) struct IPlainText {
-    source: String,
+    pub(crate) source: String,
 }
 
 impl IPlainText {