Capitalize CLAP plugin descriptor class name

To stay consistent with the rest of the naming.

src/common/serialization/clap/plugin-factory.h

@@ -31,7 +31,7 @@ struct ListResponse {
      * The descriptors for the plugins in the factory. This will be a nullopt if
      * the plugin does not support the plugin factory.
      */
-    std::optional<std::vector<clap::plugin::descriptor>> descriptors;
+    std::optional<std::vector<clap::plugin::Descriptor>> descriptors;
 
     template <typename S>
     void serialize(S& s) {

src/common/serialization/clap/plugin.cpp

@@ -21,7 +21,7 @@
 namespace clap {
 namespace plugin {
 
-descriptor::descriptor(const clap_plugin_descriptor_t& original)
+Descriptor::Descriptor(const clap_plugin_descriptor_t& original)
     : clap_version(original.clap_version),
       id((assert(original.id), original.id)),
       name((assert(original.name), original.name)),
@@ -45,7 +45,7 @@ descriptor::descriptor(const clap_plugin_descriptor_t& original)
     }
 }
 
-const clap_plugin_descriptor_t* descriptor::get() const {
+const clap_plugin_descriptor_t* Descriptor::get() const {
     // This should be the minimum of yabridge's supported CLAP version and
     // the plugin's supported CLAP version
     clap_version_t supported_clap_version = clamp_clap_version(clap_version);

src/common/serialization/clap/plugin.h

@@ -33,17 +33,17 @@ namespace plugin {
 /**
  * Owned wrapper around `clap_plugin_descriptor` for serialization purposes.
  */
-struct descriptor {
+struct Descriptor {
     /**
      * Parse a plugin-provided descriptor so it can be serialized and sent to
      * the native CLAP plugin.
      */
-    descriptor(const clap_plugin_descriptor_t& original);
+    Descriptor(const clap_plugin_descriptor_t& original);
 
     /**
      * Default constructor for bitsery.
      */
-    descriptor() {}
+    Descriptor() {}
 
     /**
      * We'll report the maximum of the plugin's supported CLAP version and