Document hexadecimal support

Author: Launch Logo Simple

README.md

@@ -256,9 +256,10 @@ TinyExpr parses the following grammar:
 In addition, whitespace between tokens is ignored.
 
 Valid variable names consist of a letter followed by any combination of:
-letters, the digits *0* through *9*, and underscore. Constants can be integers,
-decimal numbers, or in scientific notation (e.g. *1e3* for *1000*). A leading
-zero is not required (e.g. *.5* for *0.5*)
+letters, the digits *0* through *9*, and underscore. Constants can be integers
+or floating-point numbers, and can be in decimal, hexadecimal (e.g., *0x57CEF7*),
+or scientific notation (e.g., *1e3* for *1000*).
+A leading zero is not required (e.g., *.5* for *0.5*).
 
 
 ## Functions supported