feat(core): limit max marker to 0xD7FF 🙀

- to avoid mismatched surrogate pairs in markers

For: #9119

Author: srl295

core/include/ldml/keyboardprocessor_ldml.h

@@ -93,10 +93,10 @@
 #define LDML_LENGTH_VARS_ITEM 0x10
 #define LDML_LENGTH_VKEY 0xC
 #define LDML_LENGTH_VKEY_ITEM 0x8
-#define LDML_MARKER_ANY_INDEX 0xFFFE
+#define LDML_MARKER_ANY_INDEX 0xD7FF
 #define LDML_MARKER_CODE 0x8
-#define LDML_MARKER_MAX_COUNT 0xFFFC
-#define LDML_MARKER_MAX_INDEX 0xFFFD
+#define LDML_MARKER_MAX_COUNT 0xD7FD
+#define LDML_MARKER_MAX_INDEX 0xD7FE
 #define LDML_MARKER_MIN_INDEX 0x1
 #define LDML_META_SETTINGS_FALLBACK_OMIT 0x1
 #define LDML_META_SETTINGS_TRANSFORMFAILURE_OMIT 0x2

core/include/ldml/keyboardprocessor_ldml.ts

@@ -622,7 +622,7 @@ class Constants {
   /** minimum usable marker index */
   readonly marker_min_index    = 0x0001;
   /** index value referring to the 'any' marker match */
-  readonly marker_any_index    = 0xFFFE;
+  readonly marker_any_index    = 0xD7FF;
   /** maximum marker index prior to the 'any' value */
   readonly marker_max_index    = this.marker_any_index - 1;
   /** maximum count of markers (not including 'any') */