[Docs] Fixed links in sitetypes.jl to the new site (#1636)

Author: VinceNeede

src/lib/SiteTypes/src/sitetype.jl

@@ -34,7 +34,7 @@ There are currently a few built-in site types
 recognized by `jl`. The system is easily extensible
 by users. To add new operators to an existing site type,
 or to create new site types, you can follow the instructions
-[here](https://itensor.github.io/ITensors.jl/stable/examples/Physics.html).
+[here](https://docs.itensor.org/ITensorMPS/stable/examples/Physics.html).
 
 The current built-in site types are:
 
@@ -107,7 +107,7 @@ Many operators are available, for example:
 - ...
 
 You can view the internal SiteType definitions and operators
-[here](https://itensor.github.io/ITensors.jl/stable/IncludedSiteTypes.html).
+[here](https://docs.itensor.org/ITensorMPS/stable/IncludedSiteTypes.html).
 """
 SiteType(s::AbstractString) = SiteType{SmallString(s)}()
 
@@ -229,7 +229,7 @@ Sz = op("Sz", s)
 ```
 
 You can see all of the operator names defined for the site types included
-with ITensor [here](https://itensor.github.io/ITensors.jl/dev/IncludedSiteTypes.html).
+with ITensor [here](https://docs.itensor.org/ITensorMPS/stable/IncludedSiteTypes.html).
 Note that some site types such as "S=1/2" and "Qubit"
 are aliases for each other and share operator definitions.
 """