doc: mdocml.bsd.lv is now mandoc.bsd.lv

On the way switch from http to https.

gcc:
	* doc/install.texi (Prerequisites): mdocml.bsd.lv is now
	mandoc.bsd.lv.

gcc/doc/install.texi

diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 09ea87a..f4cba09 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -302,7 +302,7 @@
 The gcobol documentation is maintained as manpages using troff
 mdoc. GNU groff is required to convert them to PDF format.  Conversion
 to HTML is done with mandoc, available at
-@uref{http://mdocml.bsd.lv/}.
+@uref{https://mandoc.bsd.lv}.
 
 Because ISO COBOL defines strict requirements for numerical precision,
 gcobol requires hardware with 128-bit computation instructions.  This