Fix/add admonition blocks in docstrings

Author: abhro

src/machines.jl

@@ -1044,9 +1044,10 @@ To serialise using a different format, see [`serializable`](@ref).
 Machines are deserialized using the `machine` constructor as shown in
 the example below.
 
-> The implementation of `save` for machines changed in MLJ 0.18
->  (MLJBase 0.20). You can only restore a machine saved using older
->  versions of MLJ using an older version.
+!!! note
+    The implementation of `save` for machines changed in MLJ 0.18
+    (MLJBase 0.20). You can only restore a machine saved using older
+    versions of MLJ using an older version.
 
 ### Example
 

src/resampling.jl

@@ -752,15 +752,15 @@ Base.show(io::IO, e::CompactPerformanceEvaluation) =
 ## USER CONTROL OF DEFAULT LOGGING
 
 const DOC_DEFAULT_LOGGER =
-    """
+"""
 
-   The default logger is used in calls to [`evaluate!`](@ref) and [`evaluate`](@ref), and
-   in the constructors `TunedModel` and `IteratedModel`, unless the `logger` keyword is
-   explicitly specified.
+The default logger is used in calls to [`evaluate!`](@ref) and [`evaluate`](@ref), and
+in the constructors `TunedModel` and `IteratedModel`, unless the `logger` keyword is
+explicitly specified.
 
-   !!! note
+!!! note
 
-   Prior to MLJ v0.20.7 (and MLJBase 1.5) the default logger was always `nothing`.
+    Prior to MLJ v0.20.7 (and MLJBase 1.5) the default logger was always `nothing`.
 
 """
 

src/show.jl

@@ -34,8 +34,10 @@ MLJBase.HANDLE_GIVEN_ID[objectid(value)] = :x
 Registered objects get displayed using the variable name to which it
 was bound in calls to `show(x)`, etc.
 
-WARNING: As with any `const` declaration, binding `x` to new value of
-the same type is not prevented and the registration will not be updated.
+!!! warning
+
+    As with any `const` declaration, binding `x` to new value of
+    the same type is not prevented and the registration will not be updated.
 
 """
 macro constant(ex)