Minor typo fixes in comments

theano/tensor/opt.py

@@ -2969,14 +2969,14 @@ def local_elemwise_fusion_op(OP, max_input_fct=lambda node: 1024):
 
     :param max_input_fct: a function that returns the maximum number of inputs
                           that this elemwise can take (useful for GpuElemwise).
-                          GPU kernel currently have a limit of 256 bytes for
-                          the size of all parameter passed to it. As currently
+                          GPU kernel currently has a limit of 256 bytes for
+                          the size of all parameters passed to it. As currently
                           we pass many information only by parameter, we must
-                          limit how many op we fuse together to don't bust that
-                          256 limit.
+                          limit how many ops we fuse together to avoid busting
+                          that 256 limit.
 
                           On the CPU we limit to 1024 input variable to the
-                          resulting fused op. This is big enought that
+                          resulting fused op. This is big enough that
                           if we hit it, I'm not sure it will affect performance.
     """
     def local_fuse(node):