Update black dependency specifications for compatibility

- Remove conditional version specifications for `black` in the `dev` and `docs` groups.
- Standardise `black` versioning to `black==25.*` for all Python versions.

Author: chrimaho

pyproject.toml

@@ -49,8 +49,9 @@ dfc = "docstring_format_checker.cli:entry_point"
 
 [dependency-groups]
 dev = [
-    "black==25.*; python_version<'3.10'",
-    "black==26.*; python_version>='3.10'",
+    "black==25.*",
+    # "black==25.*; python_version<'3.10'",
+    # "black==26.*; python_version>='3.10'",
     "blacken-docs==1.*",
     "codespell==2.*",
     "ipykernel==6.*; python_version<'3.10'",
@@ -67,8 +68,9 @@ dev = [
     "pip==25.*",
 ]
 docs = [
-    "black==25.*; python_version<'3.10'",
-    "black==26.*; python_version>='3.10'",
+    "black==25.*",
+    # "black==25.*; python_version<'3.10'",
+    # "black==26.*; python_version>='3.10'",
     "docstring-inheritance==2.*; python_version<'3.10'",
     "docstring-inheritance==3.*; python_version>='3.10'",
     "livereload==2.*",