Deprecate sphinx.config.string_classes; remove all internal uses

With only a single text type across supported Python versions, the
string_classes is no longer necessary.

Internally, all uses were converted to the value `[str]`. For
.add_config_value() uses that also supply a default string, the type is
inferred.

1 files changed, 2 insertions, 3 deletions

diff --git a/sphinx/builders/htmlhelp.py b/sphinx/builders/htmlhelp.py
index ee7c0efe8..9efc75c20 100644
--- a/sphinx/builders/htmlhelp.py
+++ b/sphinx/builders/htmlhelp.py
@@ -18,7 +18,6 @@ from docutils import nodes
 
 from sphinx import addnodes
 from sphinx.builders.html import StandaloneHTMLBuilder
-from sphinx.config import string_classes
 from sphinx.environment.adapters.indexentries import IndexEntries
 from sphinx.locale import __
 from sphinx.util import logging
@@ -346,8 +345,8 @@ def setup(app):
     app.add_builder(HTMLHelpBuilder)
 
     app.add_config_value('htmlhelp_basename', default_htmlhelp_basename, None)
-    app.add_config_value('htmlhelp_file_suffix', None, 'html', string_classes)
-    app.add_config_value('htmlhelp_link_suffix', None, 'html', string_classes)
+    app.add_config_value('htmlhelp_file_suffix', None, 'html', [str])
+    app.add_config_value('htmlhelp_link_suffix', None, 'html', [str])
 
     return {
         'version': 'builtin',