chore(style): remove the trailing space from all source files (#3188)

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

docs/example_list.py

@@ -21,13 +21,13 @@ def process_index_rst(path):
       line = fp.readline()
 
     return(d)
-      
+
 h1= {
-  "get_started":"Get started", 
-  "styles":"Styles", 
-  "anim":"Animations", 
-  "event":"Events", 
-  "layouts":"Layouts", 
+  "get_started":"Get started",
+  "styles":"Styles",
+  "anim":"Animations",
+  "event":"Events",
+  "layouts":"Layouts",
   "scroll":"Scrolling",
   "widgets":"Widgets"
 }
@@ -103,7 +103,7 @@ def exec():
      d_all.update(d_act)
 
   fout.write("```eval_rst\n")
-  fout.write(".. include:: /header.rst\n") 
+  fout.write(".. include:: /header.rst\n")
   fout.write(":github_url: |github_link_base|/examples.md\n")
   fout.write("```\n")
   fout.write("\n")
@@ -111,7 +111,7 @@ def exec():
 
   for h in h1:
     fout.write("## " + h1[h] + "\n")
-    
+
     if h == "widgets":
       for w in widgets:
         fout.write("### " + widgets[w] + "\n")
@@ -121,7 +121,7 @@ def exec():
         fout.write("### " + layouts[l] + "\n")
         print_item(h + "/" + l, 4, d_all, fout)
     else:
-      print_item(h, 3, d_all, fout)   
-      
+      print_item(h, 3, d_all, fout)
+
     fout.write("")
-  
+