add Lineunit.Err method

[soypat]

No description provided.

[github-actions]

Size and Allocations fix-bug vs. main

Binary size: go +193 B, tinygo +1 B. Allocations unchanged.

Totals

go rows are the bytes of the file; tinygo rows are the loadable image plus .bss, which is what has to fit on the device.

binary	toolchain	base	head	Δ
bindiff	go	3.38 MiB	3.38 MiB	+193 B	+0.0%
bindiff	tinygo	571.66 KiB	571.66 KiB	+1 B	+0.0%

Breakdown by package

bindiff (go) — +193 B

package	base	head	Δ
github.com/soypat/tinyboot/build/xdwarf	16.42 KiB	16.53 KiB	+117 B	+0.7%
[unattributed]	2.19 MiB	2.19 MiB	+68 B	+0.0%
go:func	163.06 KiB	163.07 KiB	+8 B	+0.0%

bindiff (tinygo) — +1 B

package	base	head	Δ
[unattributed]	63.34 KiB	63.24 KiB	-104 B	-0.2%
main	34.02 KiB	34.11 KiB	+89 B	+0.3%
runtime/gc	216 B	232 B	+16 B	+7.4%