[docs][tools] Add missing "program" tags to rst files

[docs][tools] Add missing "program" tags to rst files

Sphinx allows for definitions of command-line options using
`.. option <name>` and references to those options via `:option:<name>`.
However, it looks like there is no scoping of these options by default,
meaning that links can end up pointing to incorrect documents. See for
example the llvm-mca document, which contains references to -o that,
prior to this patch, pointed to a different document. What's worse is
that these links appear to be non-deterministic in which one is picked
(on my machine, some references end up pointing to opt, whereas on the
live docs, they point to llvm-dwarfdump, for example).

The fix is to add the .. program <name> tag. This essentially namespaces
the options (definitions and references) to the named program, ensuring
that the links are kept correct.

Reviwed by: andreadb

Differential Revision: https://reviews.llvm.org/D63873

llvm-svn: 364538