macro: Add extra indentation to placeholder substitution code

The next commit will make this block conditional so pre-indent it
to clarify the simplicity of the change.
macro: Do not substitute for placeholders in bracket arguments

Fix the macro command implementation to avoid substituting macro
placeholders in bracket arguments recorded inside the macro block.
Test foreach/function/macro handling of bracket arguments

Bracket arguments recorded in command invocations inside foreach,
function, and macro blocks should not have any replacements done when
the arguments are replayed later.  Teach the RunCMake.Syntax test to
cover these cases.
Merge topic 'cmake-syntax-recorded-brackets' into next

b54dbeb Test foreach/function/macro handling of bracket arguments
ccdf7e0 macro: Do not substitute for placeholders in bracket arguments
999abb9 macro: Add extra indentation to placeholder substitution code