Type: Optical Margin Alignment hangs punctuation in right-to-left paragraphs

Optical Margin Alignment and Roman Hanging Punctuation left every
right-to-left paragraph of point and area type, and type on a path
whose first paragraph runs right to left, as it was: the quotation
marks, full stops and commas at the ends of its lines stayed inside
the margins.

A right-to-left line now hangs at the margins its alignment places it
against, as a left-to-right line does. Auto aligns a right-to-left
line at its right, so it hangs there. The line is read from right to
left: where it hangs at its left margin, a full stop and the quotation
mark after it that end the line hang together. In vertical type,
where the characters of a right-to-left paragraph run from the top
down, the pair is read from the top.

Type on a path whose first paragraph runs right to left hangs at its
brackets by the same rule. In horizontal type, Auto places it at the
end bracket, so it hangs there. On a closed path, its hang at the end
bracket gets the space between the end and start brackets before its
hang at the start bracket does, as in right-aligned type.

A justified right-to-left line of one word is spread between its
letters as they are drawn. The gap after each letter went to the
letter that follows it in the text, so the two leftmost letters
touched and the word ended one gap short of the right margin.

Docs: docs/mcp.md, docs/type-parity.md, docs/target-app-parity.md.

crates/engine/src/cmd/typecmd.rs

@@ -39,7 +39,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Optical Margin Alignment",
             ["Type"],
             None,
-            "{ids?|id?, on?: bool} turn Optical Margin Alignment on or off for the selected type and every frame of its threads (on omitted: the opposite of the first object's setting): in every left-to-right paragraph of point and area type, quotation marks, hyphens, full stops and commas at a line's start or end hang wholly outside the margin there; asterisks, tildes, ellipses, en and em dashes, colons and semicolons hang by half; and A, V, W, Y, v, w and y hang by a tenth of their advance; a left-aligned line hangs at its left margin, a right-aligned line hangs at its right margin, and centered and justified lines hang at both; left-to-right type on a path hangs at the start bracket when its line is placed there, hangs at the end bracket when the line is placed there, and hangs at both when it is centered → {on, ids}",
+            "{ids?|id?, on?: bool} turn Optical Margin Alignment on or off for the selected type and every frame of its threads (on omitted: the opposite of the first object's setting): in every paragraph of point and area type, quotation marks, hyphens, full stops and commas at a line's start or end hang wholly outside the margin there; asterisks, tildes, ellipses, en and em dashes, colons and semicolons hang by half; and A, V, W, Y, v, w and y hang by a tenth of their advance; a left-aligned line hangs at its left margin, a right-aligned line hangs at its right margin, and centered and justified lines hang at both; Auto aligns a right-to-left line at its right; type on a path hangs at the start bracket when its line is placed there, hangs at the end bracket when the line is placed there, and hangs at both when it is centered → {on, ids}",
             has_selection,
             optical_margin_alignment
         ),