[processing] update parameter name for v.segments (fix #17850)

Author: alexbruy

python/plugins/processing/algs/grass7/description/v.segment.txt

@@ -2,5 +2,5 @@ v.segment
 Creates points/segments from input vector lines and positions.
 Vector (v.*)
 ParameterVector|input|Input lines layer|1|False
-ParameterFile|file|File containing segment rules|False
+ParameterFile|rules|File containing segment rules|False
 OutputVector|output|Segments