Update obsolete URLs in documentation

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Fix obsolete mention of `darcs-all` script

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Tweak lookup semantics for GHCi macros

This changes the prefix-based lookup to prefer macros over builtins only if
the macro name matches an existing builtin name. See #8305 for more details.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>