suite retire и проверка словаря в документе для читателя

- suite retire снимает правило, конвенцию или тему: правило остаётся заглушкой
  с датой и причиной, имя уезжает в раздел выбывших, снятие с непогашенными
  ссылками отклоняется с перечнем мест
- добавлена проверка META-30: короткое описание языка обязано называть все
  слова словаря, иначе читатель копии толкует их по памяти
- retired-раздел манифеста больше не считается объявлением пути: снятый
  префикс означает, что файл ушёл вместе с ним

internal/check/suite.go

@@ -1,8 +1,11 @@
 package check
 
 import (
+	"os"
+	"path/filepath"
 	"regexp"
 	"sort"
+	"strings"
 
 	"git.vakhrushev.me/av/convy/internal/manifest"
 	"git.vakhrushev.me/av/convy/internal/suite"
@@ -15,6 +18,7 @@ func Suite(s *suite.Suite) *Report {
 	checkTopicNames(s, rep)
 	checkBaseLayers(s, rep)
 	checkSelfGoverning(s, rep)
+	checkReadingVocabulary(s, rep)
 
 	for _, d := range s.Docs {
 		checkForm(s, d, rep)
@@ -148,6 +152,42 @@ func checkSelfGoverning(s *suite.Suite, rep *Report) {
 	}
 }
 
+// checkReadingVocabulary checks that the short account of the language names
+// every word of the vocabulary (META-30).
+//
+// The full account stays with the author of the suite, while the rules are
+// applied by the reader of a copy — a person or an agent in a foreign
+// repository who holds the short one and nothing else. Let the two drift apart
+// and that reader starts reading the words by an older version: ДОПУСКАЕТСЯ
+// turns back into an everyday "you may", a departure from ДОЛЖЕН stops
+// demanding a record. Exactly what the words were introduced for fails, and it
+// fails in silence.
+func checkReadingVocabulary(s *suite.Suite, rep *Report) {
+	name := s.Manifest.Language.Reading
+	if name == "" {
+		// A suite that has not written the document yet; `suite init` says so
+		// among the next steps, and repeating it on every run is noise.
+		return
+	}
+	body, err := os.ReadFile(filepath.Join(s.Root, filepath.FromSlash(name)))
+	if err != nil {
+		// The missing file is reported by the manifest check already.
+		return
+	}
+
+	var missing []string
+	for _, word := range s.Vocab.Words() {
+		if !containsWord(string(body), word) {
+			missing = append(missing, word)
+		}
+	}
+	if len(missing) > 0 {
+		rep.Errorf(Form, name, 0,
+			"the short account of the language does not name %s: it is the only key to the text of a rule a reader of a copy holds, and a word missing from it is a word read by whatever version the reader remembers",
+			strings.Join(missing, ", "))
+	}
+}
+
 // checkBaseLayers checks that a topic holds no more than one layer without axis
 // keys. The base layer is the only one of its kind: it reaches every copy, and a
 // second such layer would mean two base texts in one assembled file.