[stmt.for] Whitespace in "while (true)".

While we don't usually care for specific formatting in the core
language, it seems valuable to allow us to stick to (and check for)
a fixed style for the control flow statements throughout the document.

Author: tkoeppe

source/statements.tex

@@ -695,7 +695,7 @@
 and the \grammarterm{expression} can be omitted.
 A missing \grammarterm{condition}
 makes the implied \keyword{while} clause
-equivalent to \tcode{while(true)}.
+equivalent to \tcode{while (true)}.
 
 \rSec2[stmt.ranged]{The range-based \keyword{for} statement}%
 \indextext{statement!range based for@range based \tcode{for}}