docs: replace V7.md with V8.md for pending breaking changes - #1550

…icing and searching (#1553)

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https://entire.io/gh/jdx/usage/trails/94
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Second pass on the size of usage-argv's help rendering, which is still
the largest piece of what usage adds to a CLI binary. Stacked on #1551
(`perf/argv-size`); merge that first, then retarget.

### What changed

- The text wrapper was inlined into `page_sections` at every call.
Keeping `write_wrapped_indented` and `wrap_lines` out of line is the
single largest saving, about 21 KB.
- About 60 `&str[a..b]` sites in `help.rs` and `help/template.rs` each
carried a bounds check and a slice-error call. They go through three
small non-inlined helpers (`head`, `tail`, `slice`), about 5 KB.
- `own_and_global` builds flag spellings with plain helpers
(`push_forms`, `has_form`, `first_long`, ...) instead of iterator
chains, and the char and string searches use one byte scan rather than
core's searcher and its monomorphised copies.
- Line and `;`/`+` splitting use one `split_line`/`split_first`; style
names are one packed string; the prose span table is a `match` (no
relocations); and several small panic sites are gone.

Help output is byte-identical (plain, forced colour, and at width 200 on
oxfmt's real CLI) and the full workspace test suite passes.

### Measured

Linux x86_64, oxlint and oxfmt built from the oxc PR with usage-argv
patched in from this branch, exact loadable-section sums against the
parent branch: oxlint 14,906,504 → 14,863,744 B (-42,760), oxfmt
9,243,420 → 9,200,652 B (-42,768).

Speed: interleaved min-of-500 `--help` is 769 µs against 780 µs for the
parent (parity; two copies of the same binary differ by about 35 µs
here). Instruction count for `oxlint --help` under cachegrind is +0.7%
(1,637,947 → 1,648,957), the price of the byte scan's first-byte filter.
Parse paths are untouched.

Ideas that need public API changes (for 8.0) are in #1550.

_This description was generated by Claude Code._

🤖 Generated with [Claude Code](https://claude.com/claude-code)

*AI-assisted — Tool: Claude Code; model: anthropic/claude-sonnet-5-5;
version: unavailable.*

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Cold-path help rendering only, with stated byte-identical output;
parse and argv handling are unchanged aside from `push_forms` in spec
layout.
> 
> **Overview**
> **Shrinks the usage-argv help renderer binary footprint** by routing
repeated string work through shared, `#[inline(never)]` helpers
(`head`/`tail`/`slice`, `find_str`/`find_byte`, `lines_of`,
`split_line`, a `Text` trait for trim/blank checks) instead of
duplicating `core` slicing and search at dozens of call sites in
`help.rs` and `help/template.rs`.
> 
> **Template and inline styling** drop static string tables for span
kinds and style names (packed `span_kind` match + `STYLE_NAMES` with
`style_index`), and flag spelling collection uses `push_forms` / small
lookup helpers rather than iterator chains.
> 
> **`page()`** now resolves path/chain once then calls `assembled_help`
/ `recursive_help` for both routed and address-based lookup; a few panic
paths become graceful `Option` handling (empty chain, implicit
positional clause).
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
ace6eb0. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Help output now handles empty command chains and missing or
unavailable items without failing.
* Implicit clauses omit the argument synopsis when no visible argument
is available.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Claude Sonnet 5.5 <noreply@anthropic.com>

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https://entire.io/gh/jdx/usage/trails/93
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### 📚 Documentation

- replace V7.md with V8.md for pending breaking changes by
[@jdx](https://github.com/jdx) in
[#1550](#1550)

### ⚡ Performance

- **(complete)** shrink completion splitting and error suggestions by
[@jdx](https://github.com/jdx) in
[#1554](#1554)
- **(lib)** shrink the help, completion and error rendering code in
usage-argv by [@jdx](https://github.com/jdx) in
[#1551](#1551)
- **(lib)** shrink the help renderer further by outlining wrapping,
slicing and searching by [@jdx](https://github.com/jdx) in
[#1553](#1553)

### 📦️ Dependency Updates

- bump jactionlint to 2.2.0 and mbx to 1.24.0 by
[@jdx](https://github.com/jdx) in
[#1549](#1549)