Add notes on Space Lua Pattern Matching (#1366)

common/space_lua/stdlib/string.ts

@@ -12,7 +12,7 @@ import printf from "./printf.ts";
 const ROSETTA_STONE = {
   "([^a-zA-Z0-9%(])-": "$1*?",
   "([^%])-([^a-zA-Z0-9?])": "$1*?$2",
-  "(.)-$": "$1*?",
+  "([^%])-$": "$1*?",
   "%a": "[a-zA-Z]",
   "%A": "[^a-zA-Z]",
   "%c": "[\x00-\x1f]",

common/space_lua/stdlib/string_test.lua

@@ -155,10 +155,13 @@ assertEqual(string.match("abc123", "%a+"), "abc")
 assertEqual(string.match("   abc", "%s+"), "   ")
 
 -- Test multiple captures
-local day, month, year = string.match("2024-03-14", "(%d+)%-(%d+)%-(%d+)")
-assertEqual(day, "2024")
+local year, month, day = string.match("2024-03-14", "(%d+)%-(%d+)%-(%d+)")
+assertEqual(year, "2024")
 assertEqual(month, "03")
-assertEqual(year, "14")
+assertEqual(day, "14")
+
+-- Test escaped hyphen at the end of a pattern
+assertEqual(string.match("4-", "%d%-"), "4-")
 
 -- Test optional captures
 local word = string.match("The quick brown fox", "%s*(%w+)%s*")