adding diagnostic message keymap for LSP

Author: joe-sinopoli

init.lua

@@ -548,6 +548,8 @@ require('lazy').setup({
           --  For example, in C this would take you to the header.
           map('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')
 
+          -- Show LSP message
+          map('gM', vim.diagnostic.open_float, '[G]oto [M]essage')
           -- The following two autocommands are used to highlight references of the
           -- word under your cursor when your cursor rests there for a little while.
           --    See `:help CursorHold` for information about when this is executed