[intseq.make] Insert spaces around - for consistency (#7608)

source/meta.tex

@@ -61,7 +61,7 @@
 \tcode{make_integer_sequence} denotes a specialization of
 \tcode{integer_sequence} with \tcode{N} non-type template arguments.
 The type \tcode{make_integer_sequence<T, N>} is an alias for the type
-\tcode{integer_sequence<T, 0, 1, ..., N-1>}.
+\tcode{integer_sequence<T, 0, 1, ..., N - 1>}.
 \begin{note}
 \tcode{make_integer_sequence<int, 0>} is an alias for the type
 \tcode{integer_sequence<int>}.