refactor: use spectraSampleIndex and use () for functions

- Use the `spectraSampleIndex()` function instead of `fromFile()`.
- Use `()` to indicate functions in the descriptive text to easily discriminate
  them from classes and parameters.

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: xcmsTutorials
 Title: Exploring and Analyzing LC-MS data with Spectra and xcms
-Version: 1.1.0
+Version: 1.1.1
 Authors@R: c(
 	     person(given = "Johannes", family = "Rainer",
 		    email = "[email protected]",

NEWS.md

@@ -1,5 +1,12 @@
 # xcmsTutorials 1.0
 
+## Changes in 1.1.1
+
+- Use `spectraSampleIndex()` instead of the old `fromFile()` function to get
+  sample assignments of individual spectra.
+- Add `()` to all functions in the descriptive text to discriminate functions
+  from classes or parameter names.
+
 ## Changes in 1.1.0
 
 - Release the tutorial to Zenodo.