Change alias to not substitute the same alias recursively

[Hoekstraa]

As of now (dev build included), alias doesn't behave like POSIX spec says.
It naively repeats substitution 10 times if a recursive loop is found.
POSIX spec however mentions:

To prevent infinite loops in recursive aliasing, if the shell is not currently processing an alias of the same name, the word shall be replaced by the value of the alias; otherwise, it shall not be replaced.

source

The current implementation can create a situation like the following (thank you, Noxebo on Discord):

How to resolve:
keep track of the last used alias, and if the same alias is used again directly after, don't substitute.

[Snarling]

This was partially addressed by #635 but we may want to do more of a rewrite to provide full recursion-detection (instead of just checking the most recent alias substitution)