Utilities/Sphinx: Avoid deprecated docutils error handling helpers

The `SafeString` and `ErrorString` classes are deprecated and will be
removed in Docutils 0.21 or later.  They help avoid encoding errors
during exception handling in Python <= 2.7, but these days we always
use Python 3 to build the documentation, at least during development,
when error cases are most likely to occur.

Fixes: #24039

Utilities/Sphinx/cmake.py

@@ -59,12 +59,6 @@ CMakeLexer.tokens["root"] = [
 
 from docutils.parsers.rst import Directive, directives
 from docutils.transforms import Transform
-try:
-    from docutils.utils.error_reporting import SafeString, ErrorString
-except ImportError:
-    # error_reporting was not in utils before version 0.11:
-    from docutils.error_reporting import SafeString, ErrorString
-
 from docutils import io, nodes
 
 from sphinx.directives import ObjectDescription
@@ -130,13 +124,13 @@ class CMakeModule(Directive):
             f = io.FileInput(source_path=path, encoding=encoding,
                              error_handler=e_handler)
         except UnicodeEncodeError as error:
-            raise self.severe('Problems with "%s" directive path:\n'
-                              'Cannot encode input file path "%s" '
-                              '(wrong locale?).' %
-                              (self.name, SafeString(path)))
+            msg = ('Problems with "%s" directive path:\n'
+                   'Cannot encode input file path "%s" '
+                   '(wrong locale?).' % (self.name, path))
+            raise self.severe(msg)
         except IOError as error:
-            raise self.severe('Problems with "%s" directive path:\n%s.' %
-                      (self.name, ErrorString(error)))
+            msg = 'Problems with "%s" directive path:\n%s.' % (self.name, error)
+            raise self.severe(msg)
         raw_lines = f.read().splitlines()
         f.close()
         rst = None