Minor corrections to some unit abbreviations

[Jagailo]

AreaMomentOfInertia:

Use superscript (cm², m³) instead of cm^2, m^3

MolarEntropy:

Use · for products (N·m instead of Nm, N*m or N.m)

SpecificEntropy:

Use · for products (N·m instead of Nm, N*m or N.m)

Using parentheses for mathematically correct display; using the correct symbol for degrees Celsius

SpecificFuelConsumption:
It looks like some unusual multiplication sign was used

WarpingMomentOfInertia:

Use superscript (cm², m³) instead of cm^2, m^3

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For ^4 and ^6 UnitParser.NormalizeUnitString() will handle this situation

[angularsen]

Good improvements! A couple of suggestions.

[angularsen]

Ok, there are a couple of minor breaking changes here, but I'll risk it.

I think very few will be upset that we no longer support parsing * or . in these unit abbreviations. I'd rather have the parser use normalization or attempt a few fallbacks to cover such alternative formats.

[Jagailo]

I work in the medical domain and our users enter units by hand.
The · symbol isn't on the keyboard, but they are too lazy to press *, so we have a huge bunch of units of different quantities ​​written with a dot, because it's faster for them.
Units with a dot are just a mistake, and * is replaced in NormalizeUnitString, so I highly doubt that this fix will be inconvenient for anyone.
We shouldn't support incorrectly written units, imho.