bug: .m files (MATLAB) show the C language icon

Describe the bug

Running eza --icons on a directory containing MATLAB .m scripts shows the C language icon (``, LANG_C) instead of a MATLAB-specific icon.

This comes from the hardcoded extension table in src/output/icons.rs:

"m" => Icons::LANG_C,

.m is used both by Objective-C and MATLAB, and eza currently always maps it to the C icon with no way to disambiguate. There's no dedicated MATLAB entry in the extension table at all.

Steps to reproduce

touch script.m
eza --icons

Expected: a MATLAB (or at least a non-C) icon. Actual: the C language icon is shown.

Workaround

Users can override this per-extension via theme.yml:

extensions:
  m: {icon: {glyph: }}

...but it would be nice to have a correct default, since .m is Objective-C's convention only by historical accident and MATLAB is at least as common a user of the extension today.

eza version

eza - A modern, maintained replacement for ls
v0.23.5 [+git]