[Console] Improved searching commands

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

I was very annoyed when I typed the command ``app/console a:d`` and I saw this exception ``The namespace "a" is ambiguous (assets, assetic)``. However, the shortcut ``a:d`` is unambiguous (``assets:install`` vs ``assetic:dump``).