patch 8.2.2487: terminal shows garbage after double-wide character

Problem:    Terminal shows garbage after double-wide character with a
            combining character. (Kyoichiro Yamada)
Solution:   Libvterm: do not add the width of the combining character to the
            glyph width. (closes #7801)

src/libvterm/src/state.c

@@ -384,7 +384,8 @@ static int on_text(const char bytes[], size_t len, void *user)
         abort();
       }
 #endif
-      width += this_width;
+      if (i == glyph_starts || this_width > width)
+	width = this_width;
     }
 
     chars[glyph_ends - glyph_starts] = 0;