Help: Revise and format add_test() command documentation

Favor the add_test(NAME) signature and document the limitations of
the plain signature.
Merge branch 'doc-add_test-cleanup' into release
Help: Format install() command documentation

Add inline markup and explicit markup blocks as appropriate.
cmInstallFilesGenerator: Add reference to calling cmMakefile

Add a Makefile member to the cmInstallFilesGenerator class and
populate it on construction.  This will be useful in a following
change to evaluate generator expressions with proper context.
install: Support generator expressions in FILES and PROGRAMS mode

Teach the install(FILES) and install(PROGRAMS) commands to evaluate
generator expressions in the list of files.

Extend the ExportImport test to cover installation cases involving
generator expressions.
Always set version variable of find_dependency macro

If there is no ARGV1, that is fine; version will be made empty, and no
version will be passed to find_package().

This is relevant when find_dependency is invoked multiple times,
sometimes with a version specified and sometimes without.

 find_dependency(dep1 3.4)
 find_dependency(dep2) # version still set to 3.4.
Merge branch 'install-FILES-genex' into release
find_dependency: Add namespacing for variables in the macro.

Avoid setting a variable called 'version' etc.
find_dependency: Ensure that ARGV1 has valid local content

The ARGV1 value could come from a wrapping context if find_dependency
is called from a function.
Merge branch 'fix-find_dependency-macro' into release