Merge branch '6.4' into 7.3

* 6.4:
  Update DOCtor-RST and enable new rule

Author: OskarStark

.doctor-rst.yaml

@@ -7,6 +7,7 @@ rules:
     composer_dev_option_not_at_the_end: ~
     correct_code_block_directive_based_on_the_content: ~
     deprecated_directive_should_have_version: ~
+    ensure_attribute_between_backticks_in_content: ~
     ensure_bash_prompt_before_composer_command: ~
     ensure_class_constant: ~
     ensure_correct_format_for_phpfunction: ~
@@ -122,3 +123,4 @@ whitelist:
         - 'End to End Tests (E2E)'
         - '.. versionadded:: 2.2.0' # Panther
         - '* Inline code blocks use double-ticks (````like this````).'
+        - 'the `HTML5 color format`_ (``/^#[0-9a-f]{6}$/i``). If it doesn''t match it,'

.github/workflows/ci.yaml

@@ -72,7 +72,7 @@ jobs:
                     key: ${{ runner.os }}-doctor-rst-${{ steps.extract_base_branch.outputs.branch }}
 
             -   name: "Run DOCtor-RST"
-                uses: docker://oskarstark/doctor-rst:1.72.0
+                uses: docker://oskarstark/doctor-rst:1.73.0
                 with:
                     args: --short --error-format=github --cache-file=/github/workspace/.cache/doctor-rst.cache