#1278 Allow linters to be defined pretty much anywhere

doc/ale.txt

@@ -2359,6 +2359,21 @@ ale#linter#Define(filetype, linter)                       *ale#linter#Define()*
   containing `.` characters will be split into individual parts, and files
   will be loaded for each filetype between the `.` characters.
 
+  Linters can be defined from vimrc and other files as long as this function
+  is loaded first. For example, the following code will define a Hello World
+  linter in vimrc in Vim 8: >
+
+  " Plugins have to be loaded first.
+  " If you are using a plugin manager, run that first.
+  packloadall
+
+  call ale#linter#Define('vim', {
+  \   'name': 'echo-test',
+  \   'executable': 'echo',
+  \   'command': 'echo hello world',
+  \   'callback': {buffer, lines -> map(lines, '{"text": v:val, "lnum": 1}')},
+  \})
+<
 
 ale#linter#Get(filetype)                                     *ale#linter#Get()*
 
@@ -2374,6 +2389,13 @@ ale#linter#Get(filetype)                                     *ale#linter#Get()*
   components.
 
 
+ale#linter#PreventLoading(filetype)               *ale#linter#PreventLoading()*
+
+  Given a `filetype`, prevent any more linters from being loaded from
+  |runtimepath| for that filetype. This function can be called from vimrc or
+  similar to prevent ALE from loading linters.
+
+
 ale#statusline#Count(buffer)                           *ale#statusline#Count()*
 
   Given the number of a buffer which may have problems, return a |Dictionary|