Describe textual representation of block params and args.
{<insn>}
endfun
```
+ * Textual presentation of block type argument in `func` has form `blk:<size>(<var_name>)`.
+ The corresponding argument in `call` insn should have analogous form
+ `blk:<the same size>(<local var name containing address of passed block data>)`
* Non-argument function variables are created through API function
`MIR_reg_t MIR_new_func_reg (MIR_context_t ctx, MIR_func_t func, MIR_type_t type, const char *name)`
* The only permitted integer type for the variable is `MIR_T_I64` (or MIR_T_U64???)
