docs: document use_gitignore in schema reference and guide (#2957)

Co-authored-by: no-hup <shauryaj.finance@gmail.com>

website/src/docs/guide.md

@@ -898,6 +898,16 @@ of the running the task is considered as a generate.
 
 :::
 
+::: tip
+
+If your globs match files that are ignored by Git (build artifacts, caches,
+etc.), you can set `use_gitignore: true` at the root of your Taskfile to
+exclude anything matched by `.gitignore` rules from `sources` and `generates`
+resolution. The setting can also be enabled or disabled per task, which takes
+precedence over the root value.
+
+:::
+
 ### Using programmatic checks to indicate a task is up to date
 
 Alternatively, you can inform a sequence of tests as `status`. If no error is

website/src/docs/reference/schema.md

@@ -208,6 +208,17 @@ set: [errexit, nounset, pipefail]
 shopt: [globstar]
 ```
 
+### `use_gitignore`
+
+- **Type**: `bool`
+- **Default**: `false`
+- **Description**: Exclude files matched by `.gitignore` rules when resolving
+  `sources` and `generates` globs for all tasks. Can be overridden per task.
+
+```yaml
+use_gitignore: true
+```
+
 ## Include
 
 Configuration for including external Taskfiles.
@@ -624,6 +635,24 @@ tasks:
       - go build -o app ./cmd
 ```
 
+#### `use_gitignore`
+
+- **Type**: `bool`
+- **Default**: `false`
+- **Description**: Exclude files matched by `.gitignore` rules when resolving
+  this task's `sources` and `generates` globs. Overrides the root-level
+  `use_gitignore` setting.
+
+```yaml
+tasks:
+  build:
+    use_gitignore: true
+    sources:
+      - '**/*.go'
+    cmds:
+      - go build ./...
+```
+
 #### `status`
 
 - **Type**: `[]string`