Render option defaults as literals

Option defaults can contain invalid characters such as backslashes.
Format them as literals to ensure they're rendered properly.

Signed-off-by: Stephen Finucane <stephen@that.guru>
Closes: #111

sphinx_click/ext.py

@@ -83,10 +83,10 @@ def _write_opts(opts: ty.List[str]) -> str:
         # Starting from Click 7.0 show_default can be a string. This is
         # mostly useful when the default is not a constant and
         # documentation thus needs a manually written string.
-        extras.append(':default: %s' % opt.show_default)
+        extras.append(':default: ``%s``' % opt.show_default)
     elif opt.default is not None and opt.show_default:
         extras.append(
-            ':default: %s'
+            ':default: ``%s``'
             % (
                 ', '.join(str(d) for d in opt.default)
                 if isinstance(opt.default, (list, tuple))

tests/test_formatter.py

@@ -213,19 +213,19 @@ def foobar(bar):
 
         .. option:: --num-param <num_param>
 
-            :default: 42
+            :default: ``42``
 
         .. option:: --param <param>
 
-            :default: Something computed at runtime
+            :default: ``Something computed at runtime``
 
         .. option:: --group <group>
 
-            :default: ('foo', 'bar')
+            :default: ``('foo', 'bar')``
 
         .. option:: --only-show-default <only_show_default>
 
-            :default: Some default computed at runtime!
+            :default: ``Some default computed at runtime!``
         """
             ).lstrip(),
             '\n'.join(output),
@@ -348,7 +348,7 @@ def foobar():
 
         .. option:: --param <param>
 
-            :default: Something computed at runtime
+            :default: ``Something computed at runtime``
 
         A sample epilog.
         """