Fixing headers in markdown docs to be displayed properly on GitHub

documentation/webdocs/markdowndocs/advanced features.md

@@ -73,8 +73,8 @@ By this design, the application can retrieve the latest data from each device su
 select last(*) from thermometers where location=’beijing’
 ```
 
-By this design, caching tool, like Redis, is not needed in the system. It will reduce the complexity of the system. 
+Through this design, caching tools like Redis are no longer needed in the system, helping reduce the complexity of the system. 
 
 TDengine creates one or more virtual nodes(vnode) in each data node. Each vnode contains data for multiple tables and has its own buffer. The buffer of a vnode is fully separated from the buffer of another vnode, not shared. But the tables in a vnode share the same buffer.  
 
-System configuration parameter cacheBlockSize configures the cache block size in bytes, and another parameter cacheNumOfBlocks configures the number of cache blocks. The total memory for the buffer of a vnode is $cacheBlockSize \times cacheNumOfBlocks$. Another system parameter numOfBlocksPerMeter configures the maximum number of cache blocks a table can use. When you create a database, you can specify these parameters. 
+System configuration parameter cacheBlockSize configures the cache block size in bytes, and another parameter cacheNumOfBlocks configures the number of cache blocks. The total memory for the buffer of a vnode is `cacheBlockSize * cacheNumOfBlocks`​. Another system parameter `numOfBlocksPerMeter` configures the maximum number of cache blocks a table can use. When you create a database, you can specify these parameters.