Add Placeholder man page template for flang docs

Author: snarang181

flang/docs/CMakeLists.txt

@@ -129,6 +129,7 @@ if (LLVM_ENABLE_SPHINX)
       add_dependencies(docs-flang-html copy-flang-src-docs)
     endif()
     if (${SPHINX_OUTPUT_MAN})
+      message(STATUS "NOTE: The Flang man page is currently a placeholder with a TODO. See docs/index.rst for details")
       add_sphinx_target(man flang SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/Source")
       add_dependencies(docs-flang-man copy-flang-src-docs)
     endif()

flang/docs/conf.py

@@ -231,7 +231,7 @@
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [("index", "flang", "Flang Documentation", ["Flang Contributors"], 1)]
+man_pages = [("index", "flang", "Flang Documentation (In Progress)", ["Flang Contributors"], 1)]
 
 # If true, show URL addresses after external links.
 # man_show_urls = False

flang/docs/index.rst

@@ -0,0 +1,11 @@
+Flang Manual Page (In Progress)
+==================================================
+
+.. note::
+    This man page is under development.
+
+For full documentation, please see the online HTML docs:
+
+https://flang.llvm.org/docs/FlangCommandLineReference.html
+
+TODO: Replace this placeholder with finalized man page content.