search: did-you-mean spelling suggestion + 9 tests

suggest/suggestN rank indexed terms by edit distance to a (misspelled) query
term, alphabetical tiebreak. 234/234.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/search/api.sx

@@ -8,7 +8,7 @@
 ;; paginate, pageTfIdf, pageBm25, resultCount, editDist, fuzzyTerms, fuzzyDocs,
 ;; fuzzyRankTfIdf, highlight, snippet, stem, stemText, stemTokens, indexStemmed,
 ;; nearDocs, expandTerm, synDocs, synRankTfIdf, queryTerms, searchRankTfIdf,
-;; searchRankBm25.
+;; searchRankBm25, suggestN, suggest.
 
 (define
   search/src
@@ -39,4 +39,6 @@
     "\n"
     search/syn-src
     "\n"
-    search/rankq-src))
+    search/rankq-src
+    "\n"
+    search/suggest-src))