Update test syntax files

test/syntax/mathjax.md

@@ -3,7 +3,7 @@
 
 ## Delimiters
 
-Delimiter                         | Format      | Expression                  | Result                    | Support
+Delimiter                         | Delimiters  | Example                     | Result                    | Support
 :---                              | :---:       | :---                        | :---:                     | :---:
 No delimiters                     | `str`       | `\sqrt{3x-1}+(1+x)^2`       | \sqrt{3x-1}+(1+x)^2       | no
 Bracket without backslash         | `[str]`     | `[\sqrt{3x-1}+(1+x)^2]`     | [\sqrt{3x-1}+(1+x)^2]     | no

test/syntax/syntax.md

@@ -289,7 +289,6 @@ var code = 'block'
 - H<sub>2</sub>O
 
 
-
 # Extras
 
 ## Emoji
@@ -309,6 +308,12 @@ var code = 'block'
 - [Examples and Syntax](highlighting.md)
 
 
+## Frontmatter
+
+- [yaml](yaml.md)
+- [toml](toml.md)
+
+
 ## Escapes
 
 <em\>HTML tags</em\>