docs(citations): migrate register line-number pointers to stable anchors

68 "register line N" pointers in tracked code and data cited the
register's line numbers directly. The register has moved since: line 334
(cited six times as RG 91 entry 8) is now rose/colour prose; lines
375-376 (cited as "RG 109 leaves Advent/Lent Ember ordinary") are now
RG 26, the paragraph that refutes that exact reading; line 374 (cited as
RG 109(a)) is now RG 25's Latin; line 378 (RG 111) is blank.
expected-divergences.sexp even wrote "RG 91 line 332" three times, as
though the line offset were part of the rubric's own identity. Since
docs/research/rules-register.md is gitignored, no reader of the public
repo could resolve any of these, and -- since the register has moved on
its own copy too -- neither can the author's.

Replaced every pointer with an anchor that survives editing: the RG
paragraph/entry number itself (already present in nearly every case,
since the citation text already names "RG 91 entry N" or "RG 109(a)"
next to the stale line number -- the line number was redundant, not
load-bearing) plus a "§4" or quoted-subsection-heading pointer into the
register for readers who want to locate the fuller discussion. Also
corrected one genuinely stale content error found while migrating its
anchor: test_precedence_ef.ml's RG33 disposition-cases comment still said
"a I/II-class vigil impeded by any Sunday" -- the pre-Task-16
mistranscription the register itself corrects to II/III class; fixed the
prose alongside its citation, since leaving a wrong RG-class claim next
to a freshly-verified anchor would be worse than the stale line number it
replaced.

Covers lib/rites/rite_ef/precedence_ef.ml (18), precedence_ef.mli
(already fixed with item 1), test/test_precedence_ef.ml (44, including
two instances that only word-wrapped "register\nline N" across a line
break and so did not match a same-line grep), and
data/ef/expected-divergences.sexp (5, including three "RG 91 line 332"
instances). All 68 original pointers resolved -- none needed guessing;
every citation's target rule was already named in the surrounding prose.

No behaviour change: every edit is a comment/citation/data-note change.
Verified byte-identical `colitur day` output across 1583, 1900, 1902,
2008, 2011, 2026, 2038, 9999. 259/259 tests green.

0 files changed, 0 insertions, 0 deletions