Support for Zlint as Zig linter (#4923)

* feat: Add Zig zlint linter and handler for ALE
* docs: Add zlint documentation to ALE Zig integration guide
* docs: Updating docs for zlint support
* tests: Adding tests for checking zlint executable and command
* refactor: Move zlint configuration test to separate test file

test/handler/test_zlint_handler.vader

@@ -0,0 +1,44 @@
+Before:
+  runtime ale_linters/zig/zlint.vim
+
+After:
+  call ale#linter#Reset()
+
+Execute(The zlint handler should parse GitHub Actions format correctly):
+  " Create a temporary buffer
+  let buffer = bufnr('')
+
+  " Define input lines
+  let input_lines = [
+  \   '::warning file=test.zig,line=61,col=47,title=unsafe-undefined::`undefined` is missing a safety comment',
+  \   '',
+  \   '::error file=test2.zig,line=4,col=33,title=no-unresolved::Unresolved import to ''test3.zig''',
+  \   '',
+  \ ]
+
+  " Define expected output
+  let expected_output = [
+  \   {
+  \     'filename': 'test.zig',
+  \     'lnum': 61,
+  \     'col': 47,
+  \     'text': '`undefined` is missing a safety comment',
+  \     'type': 'W',
+  \     'code': 'unsafe-undefined'
+  \   },
+  \   {
+  \     'filename': 'test2.zig',
+  \     'lnum': 4,
+  \     'col': 33,
+  \     'text': 'Unresolved import to ''test3.zig''',
+  \     'type': 'E',
+  \     'code': 'no-unresolved'
+  \   },
+  \ ]
+
+  " Get actual output
+  let actual_output = ale_linters#zig#zlint#Handle(buffer, input_lines)
+
+  " Assert equality
+  AssertEqual expected_output, actual_output
+

test/linter/test_zig_zlint.vader

@@ -0,0 +1,19 @@
+Before:
+  call ale#assert#SetUpLinterTest('zig', 'zlint')
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(The zlint executable and command should be configured correctly):
+  " Set a custom executable path
+  let g:ale_zig_zlint_executable = '/custom/path/to/zlint'
+
+  " Create a buffer with Zig filetype
+  call ale#test#SetFilename('test.zig')
+
+  " Check the executable
+  AssertEqual '/custom/path/to/zlint', ale#Var(bufnr(''), 'zig_zlint_executable')
+
+  " Check the command
+  let cmd = ale_linters#zig#zlint#GetCommand(bufnr(''))
+  AssertEqual ale#Escape('/custom/path/to/zlint') . ' %s -f gh', cmd