Fix inconsistent header casing

Author: abnegate

src/SDK/SDK.php

@@ -103,6 +103,9 @@ public function __construct(Language $language, Spec $spec)
         $this->twig->addFilter(new TwigFilter('caseUcfirst', function ($value) {
             return ucfirst($this->helperCamelCase($value));
         }));
+        $this->twig->addFilter(new TwigFilter('caseUcwords', function ($value) {
+            return ucwords($value, " -_");
+        }));
         $this->twig->addFilter(new TwigFilter('caseLcfirst', function ($value) {
             return lcfirst((string)$value);
         }));

templates/http/docs/example.md.twig

@@ -2,7 +2,7 @@
 {{ method.method | caseUpper }} {{spec.basePath}}{{ method.path }} HTTP/1.1
 Host: {{ spec.host }}
 {% for key, header in method.headers %}
-{{ key }}: {{ header }}{% if header == 'multipart/form-data' %}; boundary="{{boundary}}"{% endif ~%}
+{{ key | caseUcwords }}: {{ header }}{% if header == 'multipart/form-data' %}; boundary="{{boundary}}"{% endif ~%}
 {% endfor %}
 {% for key,header in spec.global.defaultHeaders %}
 {{ key }}: {{ header }}