Update global.ent Replace broken link (#182)

Author: mmalferov

entities/global.ent

@@ -455,7 +455,7 @@
 <!ENTITY url.random.gamma-section "https://dl.acm.org/doi/10.1145/3503512">
 <!ENTITY url.rar "http://www.rarlabs.com/">
 <!ENTITY url.re2c "https://re2c.org/">
-<!ENTITY url.readline "http://cnswww.cns.cwru.edu/~chet/readline/rltop.html">
+<!ENTITY url.readline "https://tiswww.case.edu/php/chet/readline/rltop.html">
 <!ENTITY url.readline.windows "http://mingweditline.sourceforge.net/">
 <!ENTITY url.recode "http://directory.fsf.org/All_GNU_Packages/recode.html">
 <!ENTITY url.rec-xml "http://www.w3.org/TR/1998/REC-xml-19980210">