Add python indentation support to docs.

Document @extend-indented and @stop-extend captures for indent queries.

book/src/generated/lang-support.md

@@ -86,7 +86,7 @@
 | prisma | ✓ |  |  | `prisma-language-server` |
 | prolog |  |  |  | `swipl` |
 | protobuf | ✓ |  | ✓ |  |
-| python | ✓ | ✓ |  | `pylsp` |
+| python | ✓ | ✓ | ✓ | `pylsp` |
 | r | ✓ |  |  | `R` |
 | racket |  |  |  | `racket` |
 | regex | ✓ |  |  |  |

book/src/guides/indent.md

@@ -46,6 +46,19 @@ capture on the same line, the indent level isn't changed at all.
 - `@outdent` (default scope `all`):
 Decrease the indent level by 1. The same rules as for `@indent` apply.
 
+- `@extend-indented`:
+Extend the range of this node to the end of the line and to lines that
+are indented more than the line that this node starts on. This is useful
+for languages like Python, where for the purpose of indentation some nodes
+(like functions or classes) should also contain indented lines that follow them.
+
+- `@stop-extend`:
+Prevents the first extension of an ancestor of this node. For example, in Python
+a return expression always ends the block that it is in. Note that this only prevents
+the next extension of one ancestor: If multiple ancestors can be extended (for example
+multiple nested conditional blocks in python), only the extension of the innermost
+ancestor is prevented.
+
 ## Predicates
 
 In some cases, an S-expression cannot express exactly what pattern should be matched.