Support astgrep (#4975)

* astgrep: support its LSP

Fixes: #4974

* astgrep: add a fixer

doc/ale-generic.txt

@@ -0,0 +1,43 @@
+===============================================================================
+ALE Generic Integration                                   *ale-generic-options*
+                                                      *ale-integration-generic*
+
+===============================================================================
+Integration Information
+
+  Some tools are not language specific.  This document collects information on
+  ale's support for these tools.
+
+
+===============================================================================
+astgrep                                                   *ale-generic-astgrep*
+
+  `'ast-grep'` is a tool which can detect code patterns and offer fixes based
+  on various languages' abstract syntax trees (ASTs) using tree-sitter.
+
+                                               *ale-options.astgrep_executable*
+                                                     *g:ale_astgrep_executable*
+                                                     *b:ale_astgrep_executable*
+astgrep_executable
+g:ale_astgrep_executable
+  Type: |String|
+  Default: `'ast-grep'`
+
+  This variable can be modified to change the executable path for
+  `ast-grep`.
+
+
+                                             *ale-options.astgrep_scan_options*
+                                                   *g:ale_astgrep_scan_options*
+                                                   *b:ale_astgrep_scan_options*
+astgrep_scan_options
+g:ale_astgrep_scan_options
+  Type: |String|
+  Default: `'--update-all'`
+
+  This variable can be modified to change the options when applying rules with
+  the `ast-grep scan` command.
+
+
+===============================================================================
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale-supported-languages-and-tools.txt

@@ -231,6 +231,8 @@ Notes:
   * `proselint`
 * FusionScript
   * `fusion-lint`
+* Generic
+  * `ast-grep`
 * Git Commit Messages
   * `gitlint`
 * Gleam

doc/ale.txt

@@ -3593,6 +3593,8 @@ documented in additional help files.
   fountain................................|ale-fountain-options|
   fusionscript............................|ale-fuse-options|
     fusion-lint...........................|ale-fuse-fusionlint|
+  generic.................................|ale-generic-options|
+    astgrep...............................|ale-generic-astgrep|
   git commit..............................|ale-gitcommit-options|
     gitlint...............................|ale-gitcommit-gitlint|
   gleam...................................|ale-gleam-options|