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Add examples for Tagged Enums, and cleanup examples

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36
docs/user-side-subtype-checking-methods.md
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@ -112,26 +112,52 @@ This RFC proposes adding 4 new methods to the [`type`](./user-defined-type-funct
The `only` methods are diffrent with how they validate, as shown below.
Example 1:
### String Enum Examples
```luau
type meow = number | "mrrp" | string
print(meow:hasonlysubtypeof(types.string)) -- false, because theres a number in the union.
print(meow:hassubtypeof(types.string)) -- true, because even though theres a number, theres also types with a subtype of string, and also string itself.
```
Example 2:
```luau
type mrow = "purr" | "meow"
print(meow:hasonlysubtypeof(types.string)) -- true, because despite the union being made up of singletons. Those singletons have the subtype of string, so it returns true.
print(meow:hassubtypeof(types.string)) -- true
```
### Tagged Enum Examples
```luau
type CatnipPurity = "90%" | "10%" | "11%"
type BaseCatnipInfo<P = CatnipPurity> = {
purity: P
}
type TwentyPercentPurityCatnip = {
purity: "20%"
name: "Average Catnip"
}
print(TwentyPercentPurityCatnip:hasonlysubtypeof(BaseCatnipInfo)) -- false, because "20%" is not an option in the string enum 'CatnipPurity'.
print(TwentyPercentPurityCatnip:hassubtypeof(BaseCatnipInfo)) -- also false for the same reason
type WeakCatnip = BaseCatnipInfo<"10%"> & {
name: "Weak Catnip"
}
print(WeakCatnip:hasonlysubtypeof(BaseCatnipInfo)) -- true, because unlike the previous example "10%" is an option in the string enum 'CatnipPurity'.
print(TwentyPercentPurityCatnip:hassubtypeof(BaseCatnipInfo)) -- also true
type FishyCatnipUnion = WeakCatnip | TwentyPercentPurityCatnip
print(FishyCatnipUnion:hasonlysubtypeof(BaseCatnipInfo)) -- false, because "20%" is not an option in the string enum 'CatnipPurity'.
print(TwentyPercentPurityCatnip:hassubtypeof(BaseCatnipInfo)) -- true, because atleast one of the components has the subtype of BaseCatnipInfo (WeakCatnip).
```
## Drawbacks
Adds extra methods to the type userdata in User-Defined type functions.
## Alternatives
Do nothing, and let users write the checks themselves as it is currently.
Do nothing, and let users write the checks themselves as it is currently.