[Bridges] explicitly document bridges not added by default

Author: odow

src/Bridges/Constraint/Constraint.jl

@@ -107,6 +107,39 @@ function add_all_bridges(model, ::Type{T}) where {T}
         model,
         ExponentialConeToScalarNonlinearFunctionBridge{T},
     )
+    # Bridges not added by default:
+    #
+    #  * FunctionConversionBridge
+    #      This bridge is not added because, even though it is not abstract, it
+    #      is highly parameterized, and parameterized versions such as
+    #      ScalarFunctionizeBridge are added.
+    #  * IndicatorSetMapBridge
+    #      This bridge is not added because, even though it is not abstract, it
+    #      is highly parameterized, and parameterized versions such as
+    #      IndicatorGreaterToLessThanBridge are added.
+    #  * NormSpecialCaseBridge
+    #      This bridge is not added because, even though it is not abstract, it
+    #      is highly parameterized, and parameterized versions such as
+    #      NormOneConeToNormConeBridge are added.
+    #  * NumberConversionBridge
+    #      This bridge is not added by default because it would silently enable
+    #      models with mixed precision. In most cases, this is a bug in the
+    #      user's code, so we leave this bridge as opt-in.
+    #  * RSOCtoNonConvexQuadBridge
+    #      This bridge is not added by default because it starts with a convex
+    #      conic constraint and generate a non-convex constraint (in the QCP
+    #      interpretation).
+    #  * SOCtoNonConvexQuadBridge
+    #      This bridge is not added by default because it starts with a convex
+    #      conic constraint and generate a non-convex constraint (in the QCP
+    #      interpretation).
+    #  * SOCtoPSDBridge
+    #      This bridge is not added because transforming the `SOC` to `RSOC` and
+    #      then to `PSD` produces a smaller SDP constraint. `RSOCtoPSDBridge` is
+    #      added by default.
+    #  * SetConversionBridge
+    #      This bridge is not added because, even though it is not abstract, it
+    #      is highly parameterized, and it intended for use by MOI extensions.
     return
 end