doc: Lee Thomas suggested the name change.

See (1994-11-04) https://groups.google.com/g/gnu.misc.discuss/c/0VtEf1fgEJk/m/IMBs2o-ftrgJ
> If GEL and GUL and GLUE don't work for the name of the scripting
> language, how about:
>
> GUILE - GNU's Universal Interpreted Language Extension
>
> (This also implies Scheme-ing, and means that the GNU's Universal
> Interpreted Language Developers would be part of a ...)
> --
> Lee Thomas

and (1994-11-22) https://groups.google.com/g/gnu.misc.discuss/c/9pD9yVoRYFw/m/0z7SLYbx8loJ
> Why "GUILE"? (GNU's Universal Interpreted Language Extension)
> Two additional reasons:
>
> 1. It does not give deliberate offense to Dr. Ousterhout or his
> supporters, thereby allowing the warring factions to eventually
> make peace (along with some others, perhaps - Gloria's 'Usband Is
> Linguistically Educated) and get back to work.
> 2. By pronunciation it offers appreciation to one of the co-inventors
> of Scheme. (Maybe a library package could be named "Scheme User
> Supported System Macros And Native-code"? OK, that's a stretch ...)
> --
> Lee Thomas,

and https://groups.google.com/g/comp.lang.scheme/c/X5GrLVAvGLU/m/Xk11xCrbzCcJ
> A while back, I started calling the language being built by the GNU Project
> GEL. It turns out that GEL is a trademark of Sybase Inc. Therefore,
> we must choose a new name. Please do not refer to the GNU language
> as GEL.
>
> My favorite proposed name, posted recently to comp.lang.scheme, is GUILE.
> I like the name, because i think programmers should be encouraged to use
> GUILE when writing programs. The name may change yet again; but for now,
> please refer to the GNU language as GUILE.
>
> -t

doc/ref/history.texi

@@ -69,7 +69,7 @@ the argument was that eventually when GEL became more capable, it
 could gain the ability to execute other languages, especially Emacs
 Lisp.
 
-Due to a naming conflict with another programming language, Jim Blandy
+Due to a naming conflict with another programming language, Lee Thomas
 suggested a new name for GEL: ``Guile''. Besides being a recursive
 acronym, ``Guile'' craftily follows the naming of its ancestors,
 ``Planner'', ``Conniver'', and ``Schemer''. (The latter was truncated