health.vim: fix highlighting

`:syntax keyword` is affected by 'iskeyword'. When we aligned
'iskeyword' to that of filetype=help, colon (:) is now included.
Simplest way to deal with this is to include colon (:) in the `:syntax
keyword` directive.

Also:
- change "SUGGESTIONS" mouthful to "ADVICE"
- change "SUCCESS" to "OK"

runtime/autoload/health.vim

@@ -1,15 +1,15 @@
 function! s:enhance_syntax() abort
   syntax case match
 
-  syntax keyword healthError ERROR
+  syntax keyword healthError ERROR[:]
         \ containedin=markdownCodeBlock,mkdListItemLine
   highlight link healthError Error
 
-  syntax keyword healthWarning WARNING
+  syntax keyword healthWarning WARNING[:]
         \ containedin=markdownCodeBlock,mkdListItemLine
   highlight link healthWarning WarningMsg
 
-  syntax keyword healthSuccess SUCCESS
+  syntax keyword healthSuccess OK[:]
         \ containedin=markdownCodeBlock,mkdListItemLine
   highlight healthSuccess guibg=#5fff00 guifg=#080808 ctermbg=82 ctermfg=232
 
@@ -102,13 +102,13 @@ function! s:format_report_message(status, msg, ...) abort " {{{
   if a:0 > 0
     let suggestions = type(a:1) == type("") ? [a:1] : a:1
     if type(suggestions) != type([])
-      echoerr "Expected String or List"
+      throw "Expected String or List"
     endif
   endif
 
   " Report each suggestion
   if len(suggestions) > 0
-    let output .= "\n    - SUGGESTIONS:"
+    let output .= "\n    - ADVICE:"
   endif
   for suggestion in suggestions
     let output .= "\n      - " . s:indent_after_line1(suggestion, 10)
@@ -124,7 +124,7 @@ endfunction " }}}
 
 " Reports a successful healthcheck.
 function! health#report_ok(msg) abort " {{{
-  echo s:format_report_message('SUCCESS', a:msg)
+  echo s:format_report_message('OK', a:msg)
 endfunction " }}}
 
 " Reports a health warning.

test/functional/plugin/health_spec.lua

@@ -1,4 +1,5 @@
 local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
 local plugin_helpers = require('test.functional.plugin.helpers')
 
 local command = helpers.command
@@ -30,13 +31,13 @@ describe('health.vim', function()
 
 
       ## Check Bar
-        - SUCCESS: Bar status
-        - SUCCESS: Other Bar status
+        - OK: Bar status
+        - OK: Other Bar status
         - WARNING: Zub
 
       ## Baz
         - WARNING: Zim
-          - SUGGESTIONS:
+          - ADVICE:
             - suggestion 1
             - suggestion 2]]),
       result)
@@ -51,15 +52,15 @@ describe('health.vim', function()
         health#success1#check
         ========================================================================
         ## report 1
-          - SUCCESS: everything is fine
+          - OK: everything is fine
 
         ## report 2
-          - SUCCESS: nothing to see here
+          - OK: nothing to see here
 
         health#success2#check
         ========================================================================
         ## another 1
-          - SUCCESS: ok
+          - OK: ok
         ]])
     end)
 
@@ -75,6 +76,36 @@ describe('health.vim', function()
         ]])
     end)
 
+    it("highlights OK, ERROR", function()
+      local screen = Screen.new(72, 10)
+      screen:attach()
+      screen:set_default_attr_ids({
+        Ok = { foreground = Screen.colors.Grey3, background = 6291200 },
+        Error = { foreground = Screen.colors.Grey100, background = Screen.colors.Red },
+      })
+      screen:set_default_attr_ignore({
+        Heading = { bold=true, foreground=Screen.colors.Magenta },
+        Heading2 = { foreground = Screen.colors.SlateBlue },
+        Bar = { foreground=Screen.colors.Purple },
+        Bullet = { bold=true, foreground=Screen.colors.Brown },
+      })
+      command("CheckHealth foo success1")
+      command("1tabclose")
+      command("set laststatus=0")
+      screen:expect([[
+        ^                                                                        |
+        health#foo#check                                                        |
+        ========================================================================|
+          - {Error:ERROR:} No healthcheck found for "foo" plugin.                       |
+                                                                                |
+        health#success1#check                                                   |
+        ========================================================================|
+        ## report 1                                                             |
+          - {Ok:OK:} everything is fine                                              |
+                                                                                |
+      ]])
+    end)
+
     it("gracefully handles invalid healthcheck", function()
       command("CheckHealth non_existent_healthcheck")
       helpers.expect([[