Rename string trim functions (#315)

Co-authored-by: Oskar Gewalli <wallymathieu@users.noreply.github.com>

src/FSharpPlus/Extensions/String.fs

@@ -82,7 +82,7 @@ module String =
     /// 
     /// Note this is distinct from trim which trims the given characters,
     /// not white spaces.
-    let trimWhiteSpaces (source: string) =
+    let trim (source: string) =
         raiseIfNull (nameof source) source
 
         source.Trim ()
@@ -151,7 +151,7 @@ module String =
         source.PadRight (totalLength, paddingChar)
 
     /// Removes all leading and trailing occurrences of specified characters from the given string.
-    let trim      (trimChars: char seq) (source: string) =
+    let trimBoth  (trimChars: char seq) (source: string) =
         raiseIfNull (nameof source) source
 
         source.Trim (Seq.toArray trimChars)