fix(eslint-plugin): [no-magic-numbers] Support negative numbers

[a-tarasyuk]

Fixes #1070

[typescript-eslint]

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[bradzacher]

did we want to handle explicitly positive numbers at the same time?
It's probably a rare case, but it might be worth chucking the handling in to make sure nobody ever complains about it?

(I don't use this rule, so IDK if it's worth the effort)
WDYT?

[a-tarasyuk]

@bradzacher

There are several Unary Operators which can potentially cause issues and which are all applied to numbers

class A {
  public readonly A = +127;
  public readonly B = -127;
  public readonly C = ~127;
  public readonly D = ++127;
  public readonly D = --127;
}

Does that make sense to handle all of them?

[bradzacher]

I don't think that people will use anything other than +/- when delcaring a constant.

++/-- form an UpdateExpression instead.
~ is a bitwise operator which I don't think is useful for defining magic number constants.

[a-tarasyuk]

@bradzacher ok, added +.

[bradzacher]

LGTM, thanks for doing this

[codecov]

Codecov Report

Merging #1072 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1072      +/-   ##
==========================================
+ Coverage   94.01%   94.02%   +0.01%     
==========================================
  Files         115      115              
  Lines        5110     5123      +13     
  Branches     1429     1434       +5     
==========================================
+ Hits         4804     4817      +13     
  Misses        177      177              
  Partials      129      129

Impacted Files	Coverage Δ
...ckages/eslint-plugin/src/rules/no-magic-numbers.ts	94.33% <100%> (+1.83%)	⬆️

[orlov-vo]

It seems like it doesn't work in enums:

enum Status {
    NONE = 0,
    START = 1,
    ERROR_DNS = -2,
    ERROR_INSTALL = -6
}

[bradzacher]

Please raise a new issue. Commenting on an old, closed PR is bad way to let us know of bugs.