Add formatting support for optional liquidDoc params

-----
Strips whitespace between optional param delimiters, and around the default value if it exists.

Author: jamesmengo

.changeset/olive-cougars-float.md

@@ -0,0 +1,5 @@
+---
+'@shopify/prettier-plugin-liquid': minor
+---
+
+Add formatting support for optional liquidDoc params and default values. Whitespace is now stripped between the optional delimiter and the param name, and around the default value if it exists.

packages/prettier-plugin-liquid/src/printer/print/liquid.ts

@@ -519,8 +519,14 @@ export function printLiquidDocParam(
     parts.push(' ', `{${node.paramType.value}}`);
   }
 
-  if (node.paramName.value) {
+  if (node.required) {
     parts.push(' ', node.paramName.value);
+  } else {
+    if (node.defaultValue?.value) {
+      parts.push(' ', `[${node.paramName.value}=${node.defaultValue.value}]`);
+    } else {
+      parts.push(' ', `[${node.paramName.value}]`);
+    }
   }
 
   if (node.paramDescription?.value) {

packages/prettier-plugin-liquid/src/test/liquid-doc/fixed.liquid

@@ -27,3 +27,23 @@ It should normalize the param description
 {% doc %}
   @param paramName - param with description
 {% enddoc %}
+
+It should strip whitespace between optional param delimiters
+{% doc %}
+  @param [paramName] - param with description
+  @param [paramName=defaultValue] - param with description
+  @param [paramName=defaultValue] - param with description
+{% enddoc %}
+
+
+It should not break params with malformed optional delimiters
+{% doc %}
+  @param [ missingTail - param with description
+  @param missingHead ] - param with description
+  @param [ too many words no type no desc]
+  @param [too many words no type ] - param with description
+  @param {String} [too many words no desc ]
+  @param {String} [ too many words = default value] - description
+  @param {String} [ too many words = default value no desc ]
+  @param {String} [ too many words = default value no type ]
+{% enddoc %}

packages/prettier-plugin-liquid/src/test/liquid-doc/index.liquid

@@ -27,3 +27,22 @@ It should normalize the param description
 {% doc %}
   @param paramName - param           with                    description
 {% enddoc %}
+
+It should strip whitespace between optional param delimiters
+{% doc %}
+  @param [    paramName         ] - param with description
+  @param [  paramName   = defaultValue] - param with description
+  @param [paramName=defaultValue      ] - param with description
+{% enddoc %}
+
+It should handle params with malformed optional delimiters
+{% doc %}
+  @param [  missingTail - param with description
+  @param missingHead  ] - param with description
+  @param [  too many words no type no desc]
+  @param [too many words no type  ] - param with description
+  @param {String} [too many words no desc ]
+  @param {String} [ too many words = default value] - description
+  @param {String} [ too many words = default value no desc  ]
+  @param {String} [ too many words = default value no type ]
+{% enddoc %}