LibPDF/CFF: Treat endchar in type 2 as type 2 "seac" when requested

With this, a character can be defined that uses two existing glyphs.
This is useful for umlauts and the like, which then just need to
reference e.g. the glyphs named "a" and "dieresis" and provide a
translation.

Makes umlauts appear on some PDFs using CFF type2 data in Type 1
fonts.

Userland/Libraries/LibPDF/Fonts/Type1FontProgram.cpp

@@ -648,8 +648,19 @@ PDFErrorOr<Type1FontProgram::Glyph> Type1FontProgram::parse_glyph(ReadonlyBytes
 
             case EndChar: {
                 maybe_read_width(Odd);
-                if (is_type2)
+                if (is_type2) {
+                    // Type 2 spec:
+                    // "In addition to the optional width (...) endchar may have four extra arguments that correspond exactly
+                    //  to the last four arguments of the Type 1 charstring command “seac”"
+                    if (state.sp == 4) {
+                        auto achar = pop();
+                        auto bchar = pop();
+                        auto ady = pop();
+                        auto adx = pop();
+                        state.glyph.set_accented_character(AccentedCharacter { (u8)bchar, (u8)achar, adx, ady });
+                    }
                     path.close();
+                }
                 break;
             }