Refactoring in commit c4e890946a (try_compile: consistently add language
properties, 2020-06-15, v3.19.0-rc1~633^2) accidentally dropped the
`_LINK` part of the name. It also miscounted array indexes in a way
that happened to propagate `CMAKE_<LANG>_LINK_NO_PIE_SUPPORTED` whether
or not it is needed for the CMP0083 NEW behavior. Simplify the code and
fix the variable name.
Fixes: #26948
- The module purpose explanation extended to clarify what this module
enables and what gets configured when not using this module.
- Examples extended with include() and some minor adjustments
- Policy CMP0083 info described with a note directive
Covers almost all blocks containing actual code, except:
* Parsed-literal blocks can't be highlighted, including many command
summaries and substitution-heavy docs like find_... commands.
This is a Sphinx limitation.
* Code with errors, like CMP0049, DEPLOYMENT_ADDITIONAL_FILES,
DEPLOYMENT_REMOTE_DIRECTORY, @PACKAGE_INIT@ substitution in the
tutorial, bracket arguments/comments in cmake-language.7 and
cmake-developer.7.
* FindQt4 module, which needs reformatting.
Rename the `CheckPIESupported` helper functions so that they
don't clobber other internal functions. Also rename them to
document they can't be unified with `CheckCompilerFlag`.
Fixes: #21497
