Add: Support zero-width space {ZWSP} to indicate where strings may break.

src/gfx_layout.cpp

@@ -93,6 +93,8 @@ static inline void GetLayouter(Layouter::LineCacheItem &line, std::string_view s
 			state.PopColour();
 		} else if (c >= SCC_FIRST_FONT && c <= SCC_LAST_FONT) {
 			state.SetFontSize((FontSize)(c - SCC_FIRST_FONT));
+		} else if (c == 0x200B) {
+			/* Zero-width space. */
 		} else {
 			/* Filter out non printable characters */
 			if (!IsPrintable(c)) continue;

src/table/strgen_tables.h

@@ -140,6 +140,7 @@ static const CmdStruct _cmd_structs[] = {
 	{"RIGHT_ARROW",       EmitSingleChar, SCC_RIGHT_ARROW,        0, -1, C_DONTCOUNT},
 	{"SMALL_LEFT_ARROW",  EmitSingleChar, SCC_LESS_THAN,          0, -1, C_DONTCOUNT},
 	{"SMALL_RIGHT_ARROW", EmitSingleChar, SCC_GREATER_THAN,       0, -1, C_DONTCOUNT},
+	{"ZWSP",              EmitSingleChar, 0x200B,                 0, -1, C_DONTCOUNT},
 
 	/* The following are directional formatting codes used to get the RTL strings right:
 	 * http://www.unicode.org/unicode/reports/tr9/#Directional_Formatting_Codes */