Tga{Importer,ImageConverter}: properly name the file format w/ extension.

For consistency with other image importing plugins.

src/MagnumPlugins/TgaImageConverter/TgaImageConverter.h

@@ -51,10 +51,11 @@ namespace Magnum { namespace Trade {
 /**
 @brief TGA image converter plugin
 
-Supports images with format @ref PixelFormat::RGB, @ref PixelFormat::RGBA or
-@ref PixelFormat::Red (or @ref PixelFormat::Luminance in OpenGL ES 2.0 and
-WebGL 1.0) and type @ref PixelType::UnsignedByte. Does *not* support
-non-default @ref PixelStorage::swapBytes() values.
+Creates Truevision TGA (`*.tga`) files from images with format
+@ref PixelFormat::RGB, @ref PixelFormat::RGBA or @ref PixelFormat::Red (or
+@ref PixelFormat::Luminance in OpenGL ES 2.0 and WebGL 1.0) and type
+@ref PixelType::UnsignedByte. Does *not* support non-default
+@ref PixelStorage::swapBytes() values.
 
 This plugin is built if `WITH_TGAIMAGECONVERTER` is enabled when building
 Magnum. To use dynamic plugin, you need to load `TgaImageConverter` plugin

src/MagnumPlugins/TgaImporter/TgaImporter.h

@@ -54,7 +54,8 @@ namespace Magnum { namespace Trade {
 /**
 @brief TGA importer plugin
 
-Supports uncompressed BGR, BGRA or grayscale images with 8 bits per channel.
+Supports Truevision TGA (`*.tga`, `*.vda`, `*.icb`, `*.vst`) uncompressed BGR,
+BGRA or grayscale images with 8 bits per channel.
 
 This plugin is built if `WITH_TGAIMPORTER` is enabled when building Magnum. To
 use dynamic plugin, you need to load `TgaImporter` plugin from