Minor README tweaks

Author: camelid

README.md

@@ -67,16 +67,16 @@ If you set g:rust_clip_command RustPlay will copy the url to the clipboard.
 
 - Mac:
 
-        let g:rust_clip_command = 'pbcopy'
+      let g:rust_clip_command = 'pbcopy'
 
 - Linux:
 
-        let g:rust_clip_command = 'xclip -selection clipboard'
+      let g:rust_clip_command = 'xclip -selection clipboard'
 
 ### Running a test under cursor
 
-In cargo project, the `:RustTest` command will run a test under the cursor.
-This is useful when your project is bigger and running all tests take longer time.
+In a Cargo project, the `:RustTest` command will run the test that is under the cursor.
+This is useful when your project is big and running all of the tests takes a long time.
 
 ## Help