Make ada_lookup_encoded_symbol "return" a struct ada_symbol_info
This makes ada_lookup_encoded_symbol more consistent with other functions
such as ada_lookup_symbol_list, and also makes it clearer in the code
using that function that symbol and block are related.
gdb/ChangeLog:
* ada-lang.c (ada_lookup_encoded_symbol): Now returns void.
Replace block_found argument by symbol_info. Adjust
implementation accordingly. Add function documentation.
(ada_lookup_symbol): Adjust to new ada_lookup_encoded_symbol.
Fix documentation.
* ada-lang.h (ada_lookup_encoded_symbol): Update declaration.
* ada-exp.y (write_object_renaming): Adjust to new
ada_lookup_encoded_symbol API.