Update filename-macros.md (MicrosoftDocs#247)

Change escaping for asterisks to something that should render properly.

Author: Colin Robertson

docs/build/filename-macros.md

@@ -18,8 +18,8 @@ Filename macros are predefined as filenames specified in the dependency (not ful
 |-----------|-------------|  
 |**$@**|Current target's full name (path, base name, extension), as currently specified.|  
 |**$$@**|Current target's full name (path, base name, extension), as currently specified. Valid only as a dependent in a dependency.|  
-|**$\***|Current target's path and base name minus file extension.|  
-|**$\*\***|All dependents of the current target.|  
+|**$***|Current target's path and base name minus file extension.|  
+|**$****|All dependents of the current target.|  
 |**$?**|All dependents with a later timestamp than the current target.|  
 |**$<**|Dependent file with a later timestamp than the current target. Valid only in commands in inference rules.|  
 
@@ -33,4 +33,4 @@ Filename macros are predefined as filenames specified in the dependency (not ful
 |**R**|Drive plus directory plus base name|  
 
 ## See Also  
- [Special NMAKE Macros](../build/special-nmake-macros.md)
+ [Special NMAKE Macros](../build/special-nmake-macros.md)