Updated the documentation build instructions for the current CMake bu…

…ild system

Reviewers: ilya-biryukov

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58603

llvm-svn: 354779

clang-tools-extra/docs/README.txt

@@ -1,11 +1,10 @@
--------------------------------------------------------------
-Documentation for the tools of clang-tools-extra repo project
--------------------------------------------------------------
+----------------------------------
+Documentation in clang-tools-extra
+----------------------------------
 
-Sphinx and doxygen documentation is generated by executing make.
+To generate documentation in HTML format from files in clang-tools-extra/docs,
+build the docs-clang-tools-html target.
 
-Sphinx html files can be generated separately using make html.
+To generate documentation from the source code using Doxygen, build the
+doxygen-clang-tools target.
 
-Doxygen html files can also be generated using make doxygen.
-
-The generated documentation will be placed in _build/html.