Update changelog & readme

CHANGELOG.md

@@ -1,10 +1,20 @@
 # Changelog
 
+## Unreleased
+
+- Added support for '{[ name ]}' syntax to allow for inserting string builder values into the
+  template using the underlying `append_builder` call instead of the `append` functon that we use
+  for strings.
+
+  Thank you to @michallepicki for the suggestion.
+
 ## 0.6.0
 
 - Added support for 'for .. as .. in ..' syntax to allow associating a type with the items in the
   list being iterated.
 
+  Thank you to @lpil for the suggestion.
+
 ## 0.5.0
 
 - Added --version flag to executable to print out current version.

README.md

@@ -44,15 +44,29 @@ Alpha. The error messages are poor and there will be plenty of flaws and oversig
 
 The syntax is inspired by [Jinja](https://jinja.palletsprojects.com/).
 
-### Value
+### String Value
 
-You can use `{{ name }}` syntax to insert the value of name into the rendered template. The
+You can use `{{ name }}` syntax to insert the value of `name` into the rendered template. The
 function generated from the template will have a labelled argument matching the identifier used.
 
 ```jinja
 {{ name }}
 ```
 
+### String Builder Value
+
+You can use `{[ name ]}` syntax to insert a string builder value into the rendered template. This
+has the advantage of using
+[string_builder.append_builder](https://hexdocs.pm/gleam_stdlib/gleam/string_builder.html#append_builder)
+in the rendered template and so it more efficient for inserting content that is already in a
+`string_builder`. This can be used to insert content from another template.
+
+The function generated from the template will have a labelled argument matching the identifier used.
+
+```jinja
+{[ name ]}
+```
+
 ### If
 
 You can use `{% %}` blocks to create an if-statement using the `if`, `else` and `endif` keywords.