fix(bw): language special characters not working for 10x14 font size (#4816)

Also cleans up the font handling to make the different font sizes more consistent.
It will now allow more than 64 special characters for language translation (if it is ever required).

radio/src/gui/common/stdlcd/utf8.cpp

@@ -21,6 +21,7 @@
 /* -*- coding: utf-8 -*- */
 
 #include <stdint.h>
+#include "fonts.h"
 #include "definitions.h"
 #include "translations/untranslated.h"
 
@@ -141,7 +142,7 @@ static unsigned char lookup_utf8_mapping(wchar_t w)
 {
   for (uint32_t i=0; i < DIM(_utf8_lut); i++) {
     if (w == _utf8_lut[i])
-      return 0x95 + (uint8_t)i; // TODO: use constant
+      return FONT_LANG_START + (uint8_t)i;
   }
   return 0x20; // return 'space' for unknown chars
 }
@@ -177,8 +178,7 @@ unsigned char map_utf8_char(const char*& s, uint8_t& len)
       len--; s++; c = *s;
       w |= c & 0x3F;
     }
-    // TODO: use constants
-    if (w >= 0x80 && w <= 0x94) { // extra chars
+    if (w >= FONT_SYMS_START && w < FONT_LANG_START) { // extra chars
       return (unsigned char)w;
     }
     if(w == L'≥')
@@ -187,7 +187,7 @@ unsigned char map_utf8_char(const char*& s, uint8_t& len)
       return STR_CHAR_BW_DEGREE;
 #if defined(UTF8_SUBS_LUT)
     auto w_map = lookup_utf8_substitution(w);
-    if (w_map> 0x95)
+    if (w_map> FONT_LANG_START)
       w_map = lookup_utf8_mapping(w_map);
     return w_map;
 #elif !defined(NO_UTF8_LUT)