Update abi.html

Co-authored-by: Jakub Jelínek <[email protected]>

Author: jicama

abi.html

@@ -5127,7 +5127,7 @@ <h5><a href="#mangling-builtin">5.1.5.2 Builtin types</a></h5>
                  ::= Dh # IEEE 754r half-precision floating point (16 bits)
                  ::= DF &lt;<a href="#mangle.number">number</a>&gt; _ # ISO/IEC TS 18661 binary floating point type _FloatN (N bits), C++23 std::floatN_t
                  ::= DF &lt;<a href="#mangle.number">number</a>&gt; x # IEEE extended precision formats, C23 _FloatNx (N bits)
-                 ::= DFb16_ # C++23 std::bfloat16_t
+                 ::= DF16b # C++23 std::bfloat16_t
                  ::= DB &lt;<a href="#mangle.number">number</a>&gt; _        # C23 signed _BitInt(N)
                  ::= DB &lt;<i>instantiation-dependent</i> <a href="#mangle.expression">expression</a>&gt; _ # C23 signed _BitInt(N)
                  ::= DU &lt;<a href="#mangle.number">number</a>&gt; _        # C23 unsigned _BitInt(N)