Remomve builtin_aliases duplicate declaration
Remomve builtin_aliases duplicate declaration

As @ehuss correctly suggested, we could just declare
in one `const` structure for every builtin alias the
following: `(alias, aliased_command, description)`.

Therefore, the suggestion has been applied and the
`BUILTIN_ALIASES` const has been refactored.

Also, the `builtin_aliases_execs` now parses the
`BUILTIN_ALIASES` const searching for a
"possible alias command" returning an option with the
previous info structure or `None`.

rustyhorde/cargo,rust-lang/cargo,tsurai/cargo,rust-lang/cargo,eminence/cargo,eminence/cargo,rust-lang/cargo,tsurai/cargo,rustyhorde/cargo,tshepang/cargo,rust-lang/cargo,nipunn1313/cargo,eminence/cargo,nipunn1313/cargo,tshepang/cargo,nipunn1313/cargo,tshepang/cargo,tsurai/cargo,tsurai/cargo,rustyhorde/cargo,nipunn1313/cargo,rustyhorde/cargo,tshepang/cargo,tsurai/cargo,eminence/cargo