Add Anagram specific properties to documentation

Signed-off-by: falkTX <falktx@falktx.com>

distrho/DistrhoInfo.hpp

@@ -869,6 +869,24 @@ START_NAMESPACE_DISTRHO
 */
 #define DISTRHO_PLUGIN_CLAP_ID "studio.kx.distrho.effect"
 
+/**
+   Plugin name abbreviation consisting of 2 or 3 characters in uppercase.
+   @note This macro is required when building plugins for the Darkglass Anagram unit.
+*/
+#define DISTRHO_PLUGIN_ABBREVIATION "DFX"
+
+/**
+   Path to a in-bundle/local 200x200 PNG image file to be used as the plugin's block image asset when OFF.
+   @note This macro is required when building plugins for the Darkglass Anagram unit.
+*/
+#define DISTRHO_PLUGIN_ANAGRAM_BLOCK_IMAGE_OFF "anagram-block-off.png"
+
+/**
+   Path to a in-bundle/local 200x200 PNG image file to be used as the plugin's block image asset when ON.
+   @note This macro is required when building plugins for the Darkglass Anagram unit.
+*/
+#define DISTRHO_PLUGIN_ANAGRAM_BLOCK_IMAGE_ON "anagram-block-on.png"
+
 /** @} */
 
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