Snippets should use ; instead of # for comment

As `#` already represent headers, use `;` as a less confusing symbol.
Also require a space between the symbol and the name.

docs/extensions/snippets.md

@@ -46,14 +46,14 @@ escaped notation
 --8<--<space>
 ```
 
-If you have a file you want to temporarily ignore, you can comment out the path by appending a `#` to the path.  This works for both single line and block format:
+If you have a file you want to temporarily ignore, you can comment out the path by appending a `; ` to the path (notice the semicolon is followed by a space).  This works for both single line and block format:
 
 ```
---8<-- "# skip.md" 
+--8<-- "; skip.md" 
 
 --8<-- 
 include.md
-# skip.md
+; skip.md
 --8<-- 
 ```
 

pymdownx/snippets.py

@@ -101,7 +101,7 @@ def parse_snippets(self, lines, file_name=None):
                         # Empty path line, insert a blank line
                         new_lines.append('')
                         continue
-                if path.startswith('#'):
+                if path.startswith('; '):
                     # path stats with '#', consider it commented out.
                     # We just removing the line.
                     continue

tests/extensions/snippets (block).txt

@@ -14,11 +14,12 @@ d.txt
     ---8<---
     d.txt
 
-    # Nested Inline
+    ; d.txt
+    # Nested inline won't work
     --8<-- "a.txt"
-    --8<-- "# b.txt"
+    --8<-- "; b.txt"
     ---8<---
 
     # Un-nested Inline
     --8<-- "a.txt"
-    --8<-- "# b.txt"
+    --8<-- "; b.txt"