Fix safe Style/ColonMethodCall offenses

Caxlsx is using both `.` and `::`, 220 occurrences vs 280 to invoke
methods on `Axlsx` module.

This commit standardizes the approach towards `.`, which will also allow
shorter lines.

Performance is not affected

```
Comparison:
      Axlsx.validate:  8515252.3 i/s
     Axlsx::validate:  8512863.7 i/s - same-ish: difference falls within error 
```

1 files changed, 8 insertions, 8 deletions

diff --git a/lib/axlsx/workbook/worksheet/sheet_view.rb b/lib/axlsx/workbook/worksheet/sheet_view.rb
index 6138cbf7..02e20b33 100644
--- a/lib/axlsx/workbook/worksheet/sheet_view.rb
+++ b/lib/axlsx/workbook/worksheet/sheet_view.rb
@@ -162,32 +162,32 @@ module Axlsx
     end
 
     # @see color_id
-    def color_id=(v); Axlsx::validate_unsigned_int(v); @color_id = v end
+    def color_id=(v); Axlsx.validate_unsigned_int(v); @color_id = v end
 
     # @see top_left_cell
     def top_left_cell=(v)
       cell = (v.instance_of?(Axlsx::Cell) ? v.r_abs : v)
-      Axlsx::validate_string(cell)
+      Axlsx.validate_string(cell)
       @top_left_cell = cell
     end
 
     # @see view
-    def view=(v); Axlsx::validate_sheet_view_type(v); @view = v end
+    def view=(v); Axlsx.validate_sheet_view_type(v); @view = v end
 
     # @see workbook_view_id
-    def workbook_view_id=(v); Axlsx::validate_unsigned_int(v); @workbook_view_id = v end
+    def workbook_view_id=(v); Axlsx.validate_unsigned_int(v); @workbook_view_id = v end
 
     # @see zoom_scale
-    def zoom_scale=(v); Axlsx::validate_scale_0_10_400(v); @zoom_scale = v end
+    def zoom_scale=(v); Axlsx.validate_scale_0_10_400(v); @zoom_scale = v end
 
     # @see zoom_scale_normal
-    def zoom_scale_normal=(v); Axlsx::validate_scale_0_10_400(v); @zoom_scale_normal = v end
+    def zoom_scale_normal=(v); Axlsx.validate_scale_0_10_400(v); @zoom_scale_normal = v end
 
     # @see zoom_scale_page_layout_view
-    def zoom_scale_page_layout_view=(v); Axlsx::validate_scale_0_10_400(v); @zoom_scale_page_layout_view = v end
+    def zoom_scale_page_layout_view=(v); Axlsx.validate_scale_0_10_400(v); @zoom_scale_page_layout_view = v end
 
     # @see zoom_scale_sheet_layout_view
-    def zoom_scale_sheet_layout_view=(v); Axlsx::validate_scale_0_10_400(v); @zoom_scale_sheet_layout_view = v end
+    def zoom_scale_sheet_layout_view=(v); Axlsx.validate_scale_0_10_400(v); @zoom_scale_sheet_layout_view = v end
 
     # Serializes the data validation
     # @param [String] str