Simplify markdown punctuation scope

caused by: sublimehq/Packages#3941

This commit ...

1. adjusts scope names
2. adjusts frontmatter contexts to follow those of syntax definitions
   like Astro/Liquid/Slim

syntaxes/Markdown.sublime-syntax

@@ -297,54 +297,62 @@ variables:
 contexts:
 
   main:
-    - include: frontmatter
+    - meta_include_prototype: false
     - match: ''
-      set: markdown
+      set: [markdown, frontmatter]
 
   frontmatter:
-    - match: (---)\s*(?i:(coffee)\s*)\n
+    - meta_include_prototype: false
+    - match: \s*(---)\s*(?i:(coffee)\s*)\n
       captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.begin.frontmatter.markdown
+        1: punctuation.section.frontmatter.begin.markdown
         2: constant.other.language-name.markdown
       embed: scope:source.coffee
       embed_scope: meta.frontmatter.markdown source.coffee.embedded.markdown
-      escape: ^(---|\.{3})\s*\n  # pandoc requires the remainder of the line to be blank
+      escape: ^\s*(---|\.{3})\s*$\n?  # pandoc requires the remainder of the line to be blank
       escape_captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.end.frontmatter.markdown
-    - match: (---)\s*(?i:(json)\s*)\n
+        1: punctuation.section.frontmatter.end.markdown
+      pop: 1
+    - match: \s*(---)\s*(?i:(json)\s*)\n
       captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.begin.frontmatter.markdown
+        1: punctuation.section.frontmatter.begin.markdown
         2: constant.other.language-name.markdown
       embed: scope:source.json
       embed_scope: meta.frontmatter.markdown source.json.embedded.markdown
-      escape: ^(---|\.{3})\s*\n # pandoc requires the remainder of the line to be blank
+      escape: ^\s*(---|\.{3})\s*$\n? # pandoc requires the remainder of the line to be blank
       escape_captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.end.frontmatter.markdown
-    - match: (---)\s*(?i:(yaml|yml)\s*)?\n
+        1: punctuation.section.frontmatter.end.markdown
+      pop: 1
+    - match: \s*(---)\s*(?i:(yaml|yml)\s*)?\n
       captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.begin.frontmatter.markdown
+        1: punctuation.section.frontmatter.begin.markdown
         2: constant.other.language-name.markdown
       embed: scope:source.yaml
       embed_scope: meta.frontmatter.markdown source.yaml.embedded.markdown
-      escape: ^(---|\.{3})\s*\n  # pandoc requires the remainder of the line to be blank
+      escape: ^\s*(---|\.{3})\s*$\n?  # pandoc requires the remainder of the line to be blank
       escape_captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.end.frontmatter.markdown
-    - match: (\+{3})\s*\n
+        1: punctuation.section.frontmatter.end.markdown
+      pop: 1
+    - match: \s*(\+{3})\s*\n
       captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.begin.frontmatter.markdown
+        1: punctuation.section.frontmatter.begin.markdown
       embed: scope:source.toml
       embed_scope: meta.frontmatter.markdown source.toml.embedded.markdown
-      escape: ^(\+{3})\s*\n
+      escape: ^\s*(\+{3})\s*$\n?
       escape_captures:
         0: meta.frontmatter.markdown
-        1: punctuation.section.block.end.frontmatter.markdown
+        1: punctuation.section.frontmatter.end.markdown
+      pop: 1
+    # Ensure to highlight frontmatter if the syntax is embedded, but pop as early as possible
+    - match: ^|(?=\S)
+      pop: 1
 
   markdown:
     - include: indented-code-blocks

syntaxes/MultiMarkdown.sublime-syntax

@@ -19,18 +19,19 @@ contexts:
       set: [markdown, frontmatter]
 
   frontmatter:
+    - meta_include_prototype: false
     # MultiMarkdown 6 supports frontmatter like headers for compatibility reasons
     # Note: The content is still limited to simple key-value pairs, no YAML!
-    - match: ^(---)\s*\n
+    - match: ^\s*(---)\s*\n
       captures:
         0: meta.frontmatter.multimarkdown
-        1: punctuation.section.block.begin.frontmatter.multimarkdown
+        1: punctuation.section.frontmatter.begin.multimarkdown
       embed: frontmatter-content
       embed_scope: meta.frontmatter.multimarkdown
-      escape: ^(---|\.{3})\s*\n
+      escape: ^\s*(---|\.{3})\s*$\n?
       escape_captures:
         0: meta.frontmatter.multimarkdown
-        1: punctuation.section.block.end.frontmatter.multimarkdown
+        1: punctuation.section.frontmatter.end.multimarkdown
       pop: 1
     # Classic key-value frontmatter beginning with first key, terminated by empty line.
     - match: ^(?={{header}})