Better doc examples for functions.

When we are in the "Custom expression" view, we can make a search for built-in functions.

We get a nice description of what it is supposed to do. Then, there is always a section "Example". The big flaw of this section is that it only shows an example of calling the functions with some overloading possibilities, but it does not show you the result of said call.

For example, the RXReplace function shows that we can call it like this: 

RXReplace("Hello", "L+", "LL", "i")

 It would be very nice to tell us what is the expected result. I guess it is "HeLLLLo" but I can't be sure, and having to test it myself is very cumbersome.

Thanks.