move vim .swp to ide section of gitignore

Author: amueller

.gitignore

@@ -1,6 +1,5 @@
 doc/generated
 examples/.ipynb_checkpoints
-*.swp
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]
@@ -73,6 +72,7 @@ target/
 
 # IDE
 .idea
+*.swp
 
 # Other
 *.pkl