less use of gap.eval in linear code

[fchapoton]

but there remains some uses in the same file

Part of #26902. Follow-up ticket: #34771

CC: @tscrim @slel @kwankyu @kliem

Component: coding theory

Author: Frédéric Chapoton

Branch: d86dd0c

Reviewer: Kwankyu Lee

Issue created by migration from https://trac.sagemath.org/ticket/34737

[fchapoton]

New commits:

d86dd0c

less use of gap.eval in linear_code

[fchapoton]

Branch: u/chapoton/34737

[fchapoton]

Commit: d86dd0c

[fchapoton]

comment:2

green lights, so please review

[kwankyu]

Reviewer: Kwankyu Lee

[kwankyu]

comment:3

LGTM. Thanks.