Fix incorrect Sphinx rename.

Author: hameerabbasi

docs/conf.py

@@ -57,7 +57,7 @@
 source_suffix = ".rst"
 
 # The main toctree document.
-main_doc = "index"
+root_doc = "index"
 
 # General information about the project.
 project = "sparse"
@@ -151,13 +151,13 @@
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
-latex_documents = [(main_doc, "sparse.tex", "sparse Documentation", "Sparse Developers", "manual")]
+latex_documents = [(root_doc, "sparse.tex", "sparse Documentation", "Sparse Developers", "manual")]
 
 # -- Options for manual page output ---------------------------------------
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [(main_doc, "sparse", "sparse Documentation", [author], 1)]
+man_pages = [(root_doc, "sparse", "sparse Documentation", [author], 1)]
 
 # -- Options for Texinfo output -------------------------------------------
 
@@ -166,7 +166,7 @@
 #  dir menu entry, description, category)
 texinfo_documents = [
     (
-        main_doc,
+        root_doc,
         "sparse",
         "sparse Documentation",
         author,