Setting extra `less` flags atop delta's defaults

My motivation for this issue is less rings the terminal bell when scrolling past the top/bottom of a diff. Silencing that bell is done via less -q/--quiet.

When delta's pager is less with no custom arguments (delta.pager, --pager, or DELTA_PAGER), delta auto-specifies sensible defaults: https://github.com/dandavison/delta/blob/0.19.2/src/utils/bat/output.rs#L174-L208

If I want to add my own configuration (i.e. -q), I have to duplicate all of delta's defaults too. There is not a nice additive way to further configure less. The request is for delta to support additive configuration of less CLI parameters. A few routes:

• A pager-args option (--pager-args, delta.pager-args) whose value is appended to the pager command delta builds, after its computed defaults.

• A leading + in delta.pager meaning "append to defaults", mirroring the + semantics DELTA_FEATURES already uses:

  ini复制

  pager = +-q

To share, the versions I have are delta 0.19.2 and less 668.