refactor(button): 使用font简写替换font-size和font-family

Author: liweijie0812

style/mobile/components/button/_index.less

@@ -3,13 +3,13 @@
 @import './_var.less';
 
 .button-size(@size) {
-  @fontSize: 'button-@{size}-font-size';
+  @font: 'button-@{size}-font';
   @padding: 'button-@{size}-padding-horizontal';
   @height: 'button-@{size}-height';
   @iconSize: 'button-@{size}-icon-size';
 
   .@{button}--size-@{size} {
-    font-size: @@fontSize;
+    font: @@font;
     padding-left: @@padding;
     padding-right: @@padding;
     height: @@height;
@@ -120,8 +120,6 @@
   transition: all 0.3s;
   border-radius: @button-border-radius;
   outline: none;
-  font-family: @button-font-family;
-  font-weight: @button-font-weight;
   vertical-align: top;
 
   .cursor-pointer();

style/mobile/components/button/_var.less

@@ -1,12 +1,11 @@
 @button-border-width: var(--td-button-border-width, 2px);
 @button-border-radius: var(--td-button-border-radius, @radius-default);
 @button-font-weight: var(--td-button-font-weight, 600);
-@button-font-family: var(--td-button-font-family, @font-family);
 
-@button-extra-small-font-size: var(--td-button-extra-small-font-size, @font-size-base);
-@button-small-font-size: var(--td-button-small-font-size, @font-size-base);
-@button-medium-font-size: var(--td-button-medium-font-size, @font-size-m);
-@button-large-font-size: var(--td-button-large-font-size, @font-size-m);
+@button-extra-small-font: var(--td-button-extra-small-font, @font-body-medium);
+@button-small-font: var(--td-button-small-font, @font-body-medium);
+@button-medium-font: var(--td-button-medium-font, @font-body-large);
+@button-large-font: var(--td-button-large-font, @font-body-large);
 
 @button-extra-small-height: var(--td-button-extra-small-height, 28px);
 @button-small-height: var(--td-button-small-height, 32px);