add escape character before underscore in type

Author: jacabuch

docs/intrinsics/arm-intrinsics.md

@@ -167,9 +167,9 @@ The primary difference between MSVC and the ARM compiler is that the MSVC adds `
 |_CountLeadingZeros||unsigned int _CountLeadingZeros(unsigned long)|
 |_CountLeadingZeros64||unsigned int _CountLeadingZeros64(unsigned \__int64)|
 |_CountTrailingZeros||unsigned _CountTrailingZeros(unsigned long)|
-|_CountTrailingZeros64||unsigned _CountTrailingZeros64(unsigned __int64)|
+|_CountTrailingZeros64||unsigned _CountTrailingZeros64(unsigned \__int64)|
 |_CountOneBits||unsigned int _CountOneBits(unsigned long)|
-|_CountOneBits64||unsigned int _CountOneBits64(unsigned __int64)|
+|_CountOneBits64||unsigned int _CountOneBits64(unsigned \__int64)|
 |_DAddSatInt|QDADD|int _DAddSatInt(int, int)|
 |_DSubSatInt|QDSUB|int _DSubSatInt(int, int)|
 |_isunordered||int _isunordered(double, double)|