Help: Fix typos

 Psuedo -> Pseudo

 behaviour -> behavior

CMake uses American spelling.
Help: Add a style guide.
Help: Mark up references to NEW and OLD policy settings properly.
Help: Use ``inline-literals`` to mark generator expressions.
Help: Add hyperlink targets to some manual sections.

These can be refered to from the command documentation and other
relevant locations.
Help: Specify how to order and modify transitively set property values.
Help: Note that the compatible interface properties must not intersect.
Help: Mark up the buildsystem commands documentation

Cross-link to the cmake-buildsystem manual.
Help: Document relation of properties to the rest of the buildsystem.
Help: Use ``True`` and ``False`` for IMPORTED values.

Only the first letter is capitalized. It is marked up.
Help: Adjust the QtAutogen properties to the common style.

Link to the cmake-qt manual.
Merge topic 'update-buildsystem-docs'

cc46b702 Help: Adjust the QtAutogen properties to the common style.
f371545d Help: Use ``True`` and ``False`` for IMPORTED values.
3879c847 Help: Document relation of properties to the rest of the buildsystem.
ba4c2fa8 Help: Mark up the buildsystem commands documentation
a683262a Help: Note that the compatible interface properties must not intersect.
fbe01bed Help: Specify how to order and modify transitively set property values.
645500b4 Help: Add hyperlink targets to some manual sections.
85a4fad7 Help: Use ``inline-literals`` to mark generator expressions.
a0fa0253 Help: Mark up references to NEW and OLD policy settings properly.
6c02e7f4 Help: Add a style guide.
91fbff88 Help: Fix typos