doc: convert remaining uses of core:: to std::.

src/etc/cmathconsts.c

@@ -13,7 +13,7 @@
 #include <math.h>
 #include <stdio.h>
 
-// must match core::ctypes
+// must match std::ctypes
 
 #define C_FLT(x) (float)x
 #define C_DBL(x) (double)x

src/etc/ziggurat_tables.py

@@ -2,7 +2,7 @@
 # xfail-license
 
 # This creates the tables used for distributions implemented using the
-# ziggurat algorithm in `core::rand::distributions;`. They are
+# ziggurat algorithm in `std::rand::distributions;`. They are
 # (basically) the tables as used in the ZIGNOR variant (Doornik 2005).
 # They are changed rarely, so the generated file should be checked in
 # to git.

src/etc/zsh/_rust

@@ -36,7 +36,7 @@ _rustc_opts_lint=(
     'path-statement[path statements with no effect]'
     'missing-trait-doc[detects missing documentation for traits]'
     'missing-struct-doc[detects missing documentation for structs]'
-    'ctypes[proper use of core::libc types in foreign modules]'
+    'ctypes[proper use of std::libc types in foreign modules]'
     "unused-mut[detect mut variables which don't need to be mutable]"
     'unused-imports[imports that are never used]'
     'heap-memory[use of any (~ type or @ type) heap memory]'