hgrc.5: use NOTE admonition paragraph

doc/hgrc.5.txt

@@ -118,7 +118,7 b' changesets. You can define subsequent al'
 
     stable5 = latest -b stable
 
-*Note*: It is possible to create aliases with the same names as
+NOTE: It is possible to create aliases with the same names as
 existing commands, which will then override the original definitions.
 This is almost always a bad idea!
 --
@@ -539,13 +539,13 b' update;;'
   in `$HG_PARENT2`. If the update succeeded, `$HG_ERROR=0`. If the
   update failed (e.g. because conflicts not resolved), `$HG_ERROR=1`.
 
-Note: it is generally better to use standard hooks rather than the
+NOTE: it is generally better to use standard hooks rather than the
 generic pre- and post- command hooks as they are guaranteed to be
 called in the appropriate contexts for influencing transactions.
 Also, hooks like "commit" will be called in all contexts that
 generate a commit (e.g. tag) and not just the commit command.
 
-Note2: Environment variables with empty values may not be passed to
+NOTE: Environment variables with empty values may not be passed to
 hooks on platforms such as Windows. As an example, `$HG_PARENT2` will
 have an empty value under Unix-like platforms for non-merge
 changesets, while it will not be available at all under Windows.