Fix two auto-indent issues with Markdown and YAML (#20193)

Closes #13376
Closes #13338

Release Notes:

- Fixed unhelpful auto-indent suggestions in markdown.
- Added `auto_indent_on_paste` setting, which can be used on a
per-language basis, to configure whether indentation should be adjusted
when pasting. This setting is enabled by default for languages other
than YAML and Markdown.

crates/language/src/language_registry.rs

@@ -965,6 +965,7 @@ impl LanguageRegistryState {
                 tab_size: language.config.tab_size,
                 hard_tabs: language.config.hard_tabs,
                 soft_wrap: language.config.soft_wrap,
+                auto_indent_on_paste: language.config.auto_indent_on_paste,
                 ..Default::default()
             }
             .clone(),