Allow users to configure ESLint's rulesCustomizations settings (#11135)

https://github.com/zed-industries/zed/assets/2072378/18f0bb28-0546-4234-a11f-39af6c9fcc12

`rulesCustomizations` is an array of rule severity overrides. Globs can
be used to apply default severities for multiple rules. See
[docs](553e632fb4/README.md (L312-L333))
& [type
definitions](553e632fb4/%24shared/settings.ts (L168))

Example Zed `settings.json` to override all eslint errors to warnings:
```jsonc
{
    "lsp": {
        "eslint": {
            "settings": {
                "rulesCustomizations": [
                    // set all eslint errors/warnings to show as warnings
                    { "rule": "*", "severity": "warn" }
                ]
            }
        }
    }
}
```


Release Notes:

- Added support for configuring ESLint's `rulesCustomizations` settings,
ie. `{"lsp": {"eslint": {"settings": {"rulesCustomizations": [{"rule":
"*", "severity": "warn"}]}}}}`

docs/src/languages/javascript.md

@@ -121,3 +121,22 @@ For example, here's how to set `problems.shortenToSingleLine`:
   }
 }
 ```
+
+#### Configure ESLint's `rulesCustomizations`:
+
+You can configure ESLint's `rulesCustomizations` setting:
+
+```json
+{
+  "lsp": {
+    "eslint": {
+      "settings": {
+        "rulesCustomizations": [
+          // set all eslint errors/warnings to show as warnings
+          { "rule": "*", "severity": "warn" }
+        ]
+      }
+    }
+  }
+}
+```