fix bold

Author: TylerMSFT

docs/build/reference/fo-object-file-name.md

@@ -12,7 +12,7 @@ Specifies an object (*`.obj`*) file name or directory to be used instead of the
 ## Syntax
 
 > **`/Fo"pathname"`\
-> **`/Fo:`**[** **]**`"pathname"`
+> **`/Fo:`**[** **]"pathname"`**
 
 ## Remarks