docs(fix[conf]): Fix version string slicing to produce '0.1' not '0.'

why: [:2] was applied to the joined string instead of the split list,
producing "0." for version "0.1.0a0". Affects search, templates, and
OpenGraph metadata.
what:
- Move [:2] inside split() call: split(".")[:2] instead of join()[:2]

Author: tony

docs/conf.py

@@ -66,7 +66,7 @@
 project = about["__title__"]
 project_copyright = about["__copyright__"]
 
-version = "{}".format(".".join(about["__version__"].split("."))[:2])
+version = "{}".format(".".join(about["__version__"].split(".")[:2]))
 release = "{}".format(about["__version__"])
 
 exclude_patterns = ["_build"]