DOC: Fix mpfr "lincense" text in readme a bit

Not mentioning LGPL is confusing, since it is LGPL it doesn't really matter for our license

Author: seberg

mpfdtype/README.md

@@ -1,7 +1,6 @@
 # A multi precision DType for NumPy
 
-:warning: Note that while the DType is BSD license, MPFR and GMP which it
-must be linked with are not.
+A DType and scalar which uses [MPFR](https://www.mpfr.org/) for multi precision floating point math.  MPFR itself has an LGPL license. 
 
 A very basic example::