doc: remove obsolete wiki references from BUILDING

Remove obsolete wiki references from BUILDING.md.

BUILDING.md

@@ -311,7 +311,7 @@ $ make
 
 ### `Intl` (ECMA-402) support:
 
-[Intl](https://github.com/nodejs/node/wiki/Intl) support is
+[Intl](https://github.com/nodejs/node/blob/master/doc/api/intl.md) support is
 enabled by default, with English data only.
 
 #### Default: `small-icu` (English only) support
@@ -321,9 +321,6 @@ the full `Intl` (ECMA-402) APIs.  It does not need to download
 any dependencies to function. You can add full
 data at runtime.
 
-*Note:* more docs are on
-[the node wiki](https://github.com/nodejs/node/wiki/Intl).
-
 #### Build with full ICU support (all locales supported by ICU):
 
 With the `--download=all`, this may download ICU if you don't have an