chore: fix clippy doc-comment warnings across the workspace

[maui1911]

Clears the long-standing doc-comment clippy debt (16 warnings under rust 1.95). Three categories, all cosmetic — no behavior changes:

• doc_lazy_continuation — lines starting with + parse as Markdown list items, making the following lines unindented continuations. Rewrapped so + never starts a line (src/sidebar.rs, src/text_field.rs, terminal/src/colors.rs).
• doc_overindented_list_items — visually-aligned bullet continuations trimmed to the 2-space Markdown standard (core/src/git.rs, core/src/theme/builtin.rs, src/command_palette.rs).
• src/app.rs — a >-initial line parsed as a blockquote (reworded to "more than TOAST_VISIBLE_CAP"), and render_group's doc block had been orphaned above the titlebar drag handler by a later insertion — moved back onto its function.

cargo clippy --workspace --all-targets reports zero doc warnings; full test suite green (647 tests). The remaining non-doc clippy findings (too-many-arguments, enum size, etc.) are intentionally out of scope.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR cleans up Rust doc comments across the workspace to eliminate Clippy doc-comment warnings (notably doc_lazy_continuation and doc_overindented_list_items) without changing runtime behavior. It standardizes doc-comment wrapping/indentation so Markdown parsing is stable (no accidental lists/quotes), and reattaches one doc block to the correct function.

Changes:

• Rewrapped doc lines so + no longer begins a doc-comment line (avoids doc_lazy_continuation).
• Adjusted list-item continuation indentation to the 2-space Markdown standard (avoids doc_overindented_list_items).
• Reworded a >-leading line and moved the render_group doc comment back onto its function.

Reviewed changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
terminal/src/colors.rs	Rewrapped doc text to avoid + starting a line in rustdoc Markdown.
src/text_field.rs	Rewrapped module docs so + is not the first character on a doc line.
src/sidebar.rs	Rewrapped/repunctuated doc text to avoid +-starting lines.
src/command_palette.rs	Fixed list continuation indentation to satisfy Markdown/Clippy expectations.
src/app.rs	Reworded a >-leading doc line and moved render_group docs onto the function.
core/src/theme/builtin.rs	Trimmed overindented list continuation in test module docs.
core/src/git.rs	Trimmed overindented list continuation in rustdoc list items.

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