[elixir] Fix README.org

Change elixir-backend from 'alchemist to 'lsp in LSP config instructions

CHANGELOG.develop

@@ -2748,10 +2748,10 @@ Other:
   Diego Alvarez, Diego Berrocal, Dietrich Daroch, Dinesh Bhosale, Dominik
   Schrempf, Doug Beardsley, dubnde, duianto, eldios, EMayej, Eugene Yaremenko,
   Evan Klitzke, Evan Niessen-Derry, firemiles, Florian Bruhin, Fuqiao Xue,
-  Garrett Johnson, Grant Shangreaux, Guido Kraemer, Henrique Jung, Henry Hirsch,
-  Henry Marshall, hornuda, Hong Xu, Ivan Fedorov, Ivan Kryvoruchko, J. Patrick
-  Lanigan, Jaremy Creechley, Jason Axelson, Jesse Cooke, Jethro Shuwen Sun, JI
-  Xiang, Jim Deville, Jody Frankowski, Joe Hillenbrand, John Eismeier, John
+  Gabriel Arrillaga, Garrett Johnson, Grant Shangreaux, Guido Kraemer, Henrique Jung,
+  Henry Hirsch, Henry Marshall, hornuda, Hong Xu, Ivan Fedorov, Ivan Kryvoruchko,
+  J. Patrick Lanigan, Jaremy Creechley, Jason Axelson, Jesse Cooke, Jethro Shuwen Sun,
+  JI Xiang, Jim Deville, Jody Frankowski, Joe Hillenbrand, John Eismeier, John
   Wood, Jon Tippens, Jonas Strømsodd, Jonathan Arnett, Jonathan Chen, Jonathan
   Gillett, Josh Greenwood, Joshua Santos, Justin Stone, Kainalu Hagiwara, Kalle
   Lindqvist, Kechao Cai, Keith Simmons, Keith Wygant, Kevin Ji, Kristoffer

layers/+lang/elixir/README.org

@@ -192,7 +192,7 @@ set the =elixir-ls-path= to the release folder of =elixir-ls= in .spacemacs =dot
 or in the layer definition
 
 #+BEGIN_SRC elisp
-  (elixir :variables elixir-backend 'alchemist elixir-ls-path "*path to folder*/elixir-ls/release")
+  (elixir :variables elixir-backend 'lsp elixir-ls-path "*path to folder*/elixir-ls/release")
 #+END_SRC
 
 by default =elixir-ls-path= is equal to ="~/elixir-ls/release"=