Update custom.txt

Author: Thutmose3

docs/custom.txt

@@ -22,7 +22,7 @@ The documentation on CSSContainer is a bit under-developed, more documentation c
 1. Configuring custom tailwind classes in settings with CRISPY_TAILWIND_STYLE
 -----------------------------------------------------------------------------
 
-Example:
+Example::
 
     CRISPY_TAILWIND_STYLE = {
         "text": "bg-gray-50 border border-gray-300",
@@ -32,7 +32,7 @@ Example:
 
 This is currently only working for the input fields and the select field. More coming soon.
 
-These are the fields you can override:
+These are the fields you can override::
 
     CRISPY_TAILWIND_STYLE = {
         "text": "",