Remove features deprecated in previous versions

test/lsp/test_did_save_event.vader

@@ -33,8 +33,8 @@ Before:
   \ 'lsp': 'stdio',
   \ 'command': 'cat - > /dev/null',
   \ 'executable': has('win32') ? 'cmd' : 'echo',
-  \ 'language_callback': 'LanguageCallback',
-  \ 'project_root_callback': 'ProjectRootCallback',
+  \ 'language': function('LanguageCallback'),
+  \ 'project_root': function('ProjectRootCallback'),
   \ })
   let g:ale_linters = {'foobar': ['dummy_linter']}
 

test/lsp/test_lsp_command_formatting.vader

@@ -24,8 +24,8 @@ Execute(Command formatting should be applied correctly for LSP linters):
   \ bufnr(''),
   \ {
   \   'name': 'linter',
-  \   'language_callback': {-> 'x'},
-  \   'project_root_callback': {-> '/foo/bar'},
+  \   'language': {-> 'x'},
+  \   'project_root': {-> '/foo/bar'},
   \   'lsp': 'stdio',
   \   'executable': has('win32') ? 'cmd': 'true',
   \   'command': '%e --foo',

test/lsp/test_lsp_custom_request.vader

@@ -25,7 +25,6 @@ Before:
   \   'name': g:linter_name,
   \   'project_root': {b -> g:project_root},
   \   'aliases': [],
-  \   'language_callback': {b -> 'cpp'},
   \   'read_buffer': 1,
   \   'command': '%e'
   \ }]