underscores in expl3 environment add to completer like subscripts

[mbertucci47]

Environment

• TeXstudio: 4.8.6 git
• Qt: 6.8.1

Expected behavior

In an expl3 environment, the underscore _ is a letter (in the TeX sense). So it shouldn't add suggestions to the completer as if it were a subscript.

Actual behavior

The expl3 commands like \fp_new_function:n are adding suggestions like \fp_new to the completer, where it thinks \fp is the base command and new is the subscript.

How to reproduce

\documentclass{article}
\begin{document}
\ExplSyntaxOn
\fp_new_function:n { mult }
\fp_set_function:nnn { mult } { a , b } { a*b }
\fp_eval:n { mult ( 3,4 ) }
\ExplSyntaxOff
\fp

\end{document}

Start the completer after \fp.