Release notes: expand clang-cl blurb a little

git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_34@196810 91177308-0d34-0410-b5e6-96231b3b80d8
Merging r195495:
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r195495 | mren | 2013-11-22 11:42:45 -0800 (Fri, 22 Nov 2013) | 5 lines

Debug Info: add a "Debug Info Version" module flag to output the current debug
info version number.

Will error out when modules have different version numbers.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_34@196812 91177308-0d34-0410-b5e6-96231b3b80d8
Merging r196143:
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r196143 | mren | 2013-12-02 11:37:35 -0800 (Mon, 02 Dec 2013) | 1 line

Expand comments for Debug Info Version.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_34@196818 91177308-0d34-0410-b5e6-96231b3b80d8
Merging r196145:
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r196145 | mren | 2013-12-02 12:10:37 -0800 (Mon, 02 Dec 2013) | 5 lines

Debug Info: Move the constant for Debug Info Version from Dwarf.h to Metadata.h.

Suggested by Eric.
Paired commit with r196144.

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_34@196820 91177308-0d34-0410-b5e6-96231b3b80d8