#1363 Make ale#engine#IsCheckingBuffer part of the public API

autoload/ale/engine.vim

@@ -76,6 +76,8 @@ function! ale#engine#InitBufferInfo(buffer) abort
     return 0
 endfunction
 
+" This function is documented and part of the public API.
+"
 " Return 1 if ALE is busy checking a given buffer
 function! ale#engine#IsCheckingBuffer(buffer) abort
     let l:info = get(g:ale_buffer_info, a:buffer, {})

doc/ale.txt

@@ -1907,6 +1907,13 @@ ale#engine#GetLoclist(buffer)                         *ale#engine#GetLoclist()*
   be copied before applying |map()| or |filter()|.
 
 
+ale#engine#IsCheckingBuffer(buffer)             *ale#engine#IsCheckingBuffer()*
+
+  Given a buffer number, returns `1` when ALE is busy checking that buffer.
+
+  This function can be used for status lines, tab names, etc.
+
+
 ale#engine#ManageFile(buffer, filename)               *ale#engine#ManageFile()*
 
   Given a buffer number for a buffer currently running some linting tasks