minor fix

Author: chrisjsewell

markdown_it/extensions/myst_blocks/index.py

@@ -5,7 +5,7 @@
 from markdown_it.common.utils import charCodeAt, isSpace, escapeHtml
 
 
-TARGET_PATTERN = re.compile(r"^\(([a-zA-Z\_\-\+\:]{1,36})\)\=\s*$")
+TARGET_PATTERN = re.compile(r"^\(([a-zA-Z0-9\_\-\+\:]{1,36})\)\=\s*$")
 
 
 def myst_block_plugin(md: MarkdownIt):