Fix -d alias conflict: --deep vs --debug (#3074)

[hariprakazz]

This PR removes the -d alias from --deep to fix its conflict with --debug.

• --debug functionality is fully preserved.
• CI failures on Alpine/LDC are unrelated to this change (all DMD builds pass).
• This small change ensures -d=VALUE works correctly for defining debug version identifiers.

Fixes #3074

[hariprakazz]

Hi Maintainers,

This PR fixes the -d alias conflict between --deep and --debug as described in #3074.

The short -d alias has been removed from --deep.

--debug functionality is fully preserved (-d=VALUE now works correctly).

All DMD builds pass, and the change is minimal.

CI failures on LDC/Alpine/MacOS are unrelated to this change.