fix(cmd/chroma): --html-styles ignores the other --html-* flags

[VXNCXNX]

Stacked on #1347, which is needed for cmd/chroma to build at all.

--html-styles ignores every other --html-* flag.

$ chroma --html-styles --html-prefix=foo- --html-tab-width=4 | head -2
/* Background */ .bg { color: #e5e5e5; background-color: #000000; }
/* PreWrapper */ .chroma { color: #e5e5e5; background-color: #000000; -webkit-text-size-adjust: none; }

After:

/* Background */ .foo-bg { color: #e5e5e5; background-color: #000000;tab-size: 4; }
/* PreWrapper */ .foo-chroma { color: #e5e5e5; background-color: #000000;tab-size: 4; -webkit-text-size-adjust: none; }

Generating a stylesheet is exactly when --html-prefix matters most, since the prefix has to agree with whatever generated the HTML. Emitting unprefixed CSS produces a stylesheet that silently matches nothing.

Cause

if cli.Formatter == "html" {
	configureHTMLFormatter(ctx)
}

but --html-styles writes CSS from the html formatter regardless of which formatter is selected. So unless you also pass -f html, which is pointless when you only want the stylesheet, the html options are never applied.

Same for --html-lines-table, --html-highlight, --html-linkable-lines and the rest of the group.

The fix

A small usesHTMLFormatter() covering both cases, at the one call site.

Unchanged, checked before and after: -f html --html-prefix=zz- still emits zz-chroma, and a bare --html-styles with no other flags is byte-identical.

Verification

TestHTMLStylesAppliesHTMLOptions in cmd/chroma/main_test.go sets cli.Formatter = "terminal" with --html-styles, --html-prefix and --html-tab-width, then asserts both appear in the CSS.

Reverting the condition to cli.Formatter == "html" fails it:

--- FAIL: TestHTMLStylesAppliesHTMLOptions
    main_test.go:29: expected html formatter to be in use

go test ./... passes in both the root module and cmd/chroma, and golangci-lint run at the root is clean.

Disclosure: written with AI assistance (Claude Code). I built both binaries, produced the before and after above by running them, and ran the revert check myself.

[alecthomas]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Hooray!

Reviewed commit: 139906dca7

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