[thread.thread.id] Fix wrong uses of "shall"

Author: K-ballo

source/threads.tex

@@ -395,7 +395,7 @@
 does not represent threads of execution.
 
 \pnum
-\tcode{thread::id} shall be a trivially copyable class\iref{class}.
+\tcode{thread::id} is a trivially copyable class\iref{class}.
 The library may reuse the value of a \tcode{thread::id} of a terminated thread that can no longer be joined.
 
 \pnum
@@ -481,8 +481,8 @@
 \begin{itemdescr}
 \pnum\effects Inserts an unspecified text representation of \tcode{id} into
 \tcode{out}. For two objects of type \tcode{thread::id} \tcode{x} and \tcode{y},
-if \tcode{x == y} the \tcode{thread::id} objects shall have the same text
-representation and if \tcode{x != y} the \tcode{thread::id} objects shall have
+if \tcode{x == y} the \tcode{thread::id} objects have the same text
+representation and if \tcode{x != y} the \tcode{thread::id} objects have
 distinct text representations.
 
 \pnum\returns \tcode{out}.