Fix comment typo.

Author: pooka109

crawl-ref/source/defines.h

@@ -12,7 +12,7 @@
 #include "macros.h"
 
 // In this case, an x86 CPU will use x87 math for floating point calculations,
-// which uses 80 bit intermediate results, andleads to difference from the
+// which uses 80 bit intermediate results, and leads to difference from the
 // (much more common, in 2019) SSE-based calculations.
 // probably far from the only case where seeding isn't reliable...
 #if defined(TARGET_CPU_X86) && !defined(__SSE__)