[basic.start.main] Add spaces around operator -

Author: Andreas-Krug

source/basic.tex

@@ -6864,7 +6864,7 @@
 arguments passed to the program from the environment in which the
 program is run. If
 \tcode{argc} is nonzero these arguments shall be supplied in
-\tcode{argv[0]} through \tcode{argv[argc-1]} as pointers to the initial
+\tcode{argv[0]} through \tcode{argv[argc - 1]} as pointers to the initial
 characters of null-terminated multibyte strings (\ntmbs{}s)\iref{multibyte.strings}
 and \tcode{argv[0]} shall be the pointer to
 the initial character of an \ntmbs{} that represents the name used to