Refine qWasmCallStack documentation (llvm#163803)

`qWasmCallStack` documentation is not clear enough in how the list of PC
values is delimited and the size of these values.

Author: MaxDesiatov

lldb/docs/resources/lldbgdbremote.md

@@ -2491,9 +2491,10 @@ The packet below are supported by the
 ### qWasmCallStack
 
 Get the Wasm call stack for the given thread id. This returns a hex-encoded
-list of PC values, one for each frame of the call stack. To match the Wasm
-specification, the addresses are encoded in little endian byte order, even if
-the endian of the Wasm runtime's host is not little endian.
+list (with no delimiters) of 64-bit PC values, one for each frame of the call
+stack. To match the Wasm specification, the addresses are encoded in little
+endian byte order, even if the endian of the Wasm runtime's host is not little
+endian.
 
 ```
 send packet: $qWasmCallStack:202dbe040#08