[C++ for OpenCL] Misc formattings/clarifications (#516)

Improved section on address spaces:
- Fixed formatting of spec ref
- Add minor clarifications

Co-authored-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

Author: AnastasiaStulova

cxx4opencl/address_spaces.txt

@@ -9,7 +9,7 @@
 
 This section only documents behavior related to {cpp} features. For example
 conversion rules are extended from the qualification conversion {cpp}17
-[conv.qual] but the compatibility is determined using notation of sets and
+`[conv.qual]` but the compatibility is determined using notation of sets and
 overlapping of address spaces from Embedded C
 (`ISO/IEC JTC1 SC22 WG14 N1021 s3.1.3`). For OpenCL it means that implicit
 conversions are allowed from a named address space (except for `+__constant+`)
@@ -20,13 +20,13 @@ space exists. Most of the rules follow this logic.
 
 ==== Casts
 
-C-style casts follow rules of `OpenCL C v2.0 s6.5.5`. Conversions to generic
-address space can be made by any {cpp} cast operator (as an implicit
-conversion); converting from generic to named address space can only be done
-using the dedicated `addrspace_cast` operator. Operator `addrspace_cast` can only
-convert between address spaces and no other conversions are allowed to occur.
-Note that conversions between `__constant` and any other other address space
-are disallowed.
+C-style casts follow rules of `OpenCL C v2.0 s6.5.5`. Conversions of
+pointers and references to the generic address space can be done by any {cpp} cast
+operator (as an implicit conversion); converting from generic to named address
+space can only be done using the dedicated `addrspace_cast` operator. The
+`addrspace_cast` operator can only convert between address spaces for pointers and references
+and no other conversions are allowed to occur. Note that conversions between
+`__constant` and any other other address space are disallowed.
 
 [source,cpp]
 ----------
@@ -88,7 +88,7 @@ Address spaces are not deduced for:
     specializations or non-type type based template parameters.
   * non-pointer/non-reference class members except for static data members
     that are deduced to `+__global+` address space.
-  * non-pointer/non-reference alias declarations.
+  * non-pointer/non-reference type alias declarations.
   * decltype expressions.
 
 [source,cpp]
@@ -152,7 +152,7 @@ __kernel void foo()
                   // (addr space of a pointer is deduced regularly,
                   // addr space of its pointee is taken from 'i').
 
-  auto *&refptr = ptr; // type of 'refptr' is '__local int * & __private'
+  auto *&refptr = ptr; // type of 'refptr' is '__local int * generic & __private'
                        // (addr space of a reference and type of referencing object
                        // is deduced regularly,
                        // addr space of a pointee is taken from the pointee of 'ptr').