Add a fix for Symbol#inspect on 3.0, 3.1

[prikha]

Original bug:
https://bugs.ruby-lang.org/issues/18905

Resolves: #359

[mbj]

@prikha if you had mutation tested this on 3.1, it should have forced you into value[-1].eql?('=') which is better code as it uses the non coercing #== (even if coercion does not trigger here in the first place, its just less powerful primitive).

But in addition, I do not think we should pull a string out to than compare with a literal. We can AFAIK just directly uses regexps so value.match?(/=\z/). This creates no intermediary objects and avoids also to access out of bounds on empty symbols.

[prikha]

Applied

[mbj]

@prikha I'm well aware I probably did this wrong within unparser at other places, but I think we should use: RUBY_VERSION < '3.2.' note the extra . If ruby ever where to get a minor version of like: 3.11 it would despite logically being bigger, be lexicographical sorted wrong.

[mbj]

Next question, how do we know that only = suffix symbols are affected?

I wounder if we should instead do something "stupid" and on RUBY < '3.2.' do a round trip on #inspect and if that fails add the quotes, and raise if that also fails.

[prikha]

Let's go with a single roundtrip. Second one seems to be an overkill to me.

[prikha]

Applied