Update README.md

Fix typo

README.md

@@ -89,10 +89,10 @@ This means you consider the first two branches at each depth for expansion, but
 
 #### Algorithm parameters
 
-An overview of selveral parameters that the algorithms support:
+An overview of several parameters that the algorithms support:
 
  * filterWidth - when set considers only the first filterWidth branches from a state for expansion
  * depthLimit - search up to a specific depth only, useful, e.g., when states would be able to expand infinitely
  * backtrackLimit - limits the total number of backtrack operations, a backtracks occurs whenever the search has to return to a node closer to the root than the current one
  * beamWidth - a beam is a set of states that are expanded in parallel, the beamWidth defines the maximum size of that set
- * rakeWidth - the rakeWidth defines the number of states to reach at a certain level, before switching to depth-first search
+ * rakeWidth - the rakeWidth defines the number of states to reach at a certain level, before switching to depth-first search