update description of libraries

README.md

@@ -6,7 +6,8 @@ single-file public domain libraries for C/C++
 library | description
 --------- | ---------
 **stb_image.c**       | image loading/decoding from disk/memory: JPG, PNG, TGA, BMP, PSD,GIF,HDR,PIC
-**stb_vorbis.c**      | decode 
+**stb_vorbis.c**      | decode ogg vorbis files from memory to float/16-bit signed output
+**stb_truetype.h**    | parse, decode, and rasterize characters from truetype fonts
 **stb_image_write.h** | image writing to disk
 **stb.h**             | helper functions for C, mostly redundant in C++
 **stb_c_lexer.h**     | simplify writing parsers for C-like languages