[indic] Fix shaping of U+0AFB GUJARATI SIGN SHADDA

Fixes https://github.com/behdad/harfbuzz/issues/552

src/hb-ot-shape-complex-indic-private.hh

@@ -123,7 +123,7 @@ enum indic_syllabic_category_t {
   INDIC_SYLLABIC_CATEGORY_CONSONANT_SUBJOINED		= OT_CM,
   INDIC_SYLLABIC_CATEGORY_CONSONANT_SUCCEEDING_REPHA	= OT_N,
   INDIC_SYLLABIC_CATEGORY_CONSONANT_WITH_STACKER	= OT_CS,
-  INDIC_SYLLABIC_CATEGORY_GEMINATION_MARK		= OT_SM,
+  INDIC_SYLLABIC_CATEGORY_GEMINATION_MARK		= OT_SM, /* https://github.com/behdad/harfbuzz/issues/552 */
   INDIC_SYLLABIC_CATEGORY_INVISIBLE_STACKER		= OT_Coeng,
   INDIC_SYLLABIC_CATEGORY_JOINER			= OT_ZWJ,
   INDIC_SYLLABIC_CATEGORY_MODIFYING_LETTER		= OT_X,

src/hb-ot-shape-complex-indic.cc

@@ -220,6 +220,8 @@ set_indic_properties (hb_glyph_info_t &info)
   else if (unlikely (u == 0x11303u)) cat = OT_SM;
   else if (unlikely (u == 0x1133cu)) cat = OT_N;
 
+  else if (unlikely (u == 0x0AFBu)) cat = OT_N; /* https://github.com/behdad/harfbuzz/issues/552 */
+
   else if (unlikely (u == 0x0980u)) cat = OT_PLACEHOLDER; /* https://github.com/behdad/harfbuzz/issues/538 */
   else if (unlikely (u == 0x17C6u)) cat = OT_N; /* Khmer Bindu doesn't like to be repositioned. */
   else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x2010u, 0x2011u)))