{Wav,Any}AudioImporter: make the plugins searchable by their names too.

src/MagnumPlugins/AnyAudioImporter/AnyImporter.h

@@ -55,6 +55,8 @@ namespace Magnum { namespace Audio {
 /**
 @brief Any audio importer plugin
 
+@m_keywords{AnyAudioImporter}
+
 Detects file type based on file extension, loads corresponding plugin and then
 tries to open the file with it.
 

src/MagnumPlugins/WavAudioImporter/WavImporter.h

@@ -57,6 +57,8 @@ namespace Magnum { namespace Audio {
 /**
 @brief WAV importer plugin
 
+@m_keywords{WavAudioImporter}
+
 Supports mono and stereo files of the following formats:
 
 -   8 bit per channel PCM, imported as @ref BufferFormat::Mono8 and