fix ant-design#12395. input group hover style error (ant-design#12407)

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* [x] Make sure that you propose PR to right branch: bugfix for `master`, feature for branch `feature`.
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* [x] Run `npm run lint` and fix those errors before submitting in order to keep consistent code style.
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Extra checklist:

**if** *isBugFix* **:**

  * [x] Make sure that you add at least one unit test for the bug which you had fixed.

**elif** *isNewFeature* **:**

  * [ ] Update API docs for the component.
  * [ ] Update/Add demo to demonstrate new feature.
  * [ ] Update TypeScript definition for the component.
  * [ ] Add unit tests for the feature.

components/cascader/style/index.less

@@ -13,7 +13,7 @@
  background-color: transparent !important;
  cursor: pointer;
  width: 100%;
- position: static;
+ position: relative;
  }
 
  &-picker-show-search &-input.@{ant-prefix}-input {

components/input/style/mixin.less

@@ -263,6 +263,21 @@
  display: block;
  .clearfix;
 
+ &-addon,
+ &-wrap,
+ > .@{inputClass} {
+ &:not(:first-child):not(:last-child) {
+ border-right-width: 1px;
+ border-right-color: transparent;
+ &:hover {
+ .hover();
+ }
+ &:focus {
+ .active();
+ }
+ }
+ }
+
  & > * {
  border-radius: 0;
  border-right-width: 0;
@@ -289,7 +304,14 @@
  & > .@{ant-prefix}-mention-wrapper .@{ant-prefix}-mention-editor,
  & > .@{ant-prefix}-time-picker .@{ant-prefix}-time-picker-input {
  border-radius: 0;
- border-right-width: 0;
+ border-right-width: 1px;
+ border-right-color: transparent;
+ &:hover {
+ .hover();
+ }
+ &:focus {
+ .active();
+ }
  }
 
  & > *:first-child,
@@ -308,11 +330,22 @@
  & > .@{ant-prefix}-calendar-picker:last-child .@{ant-prefix}-input,
  & > .@{ant-prefix}-select-auto-complete:last-child .@{ant-prefix}-input,
  & > .@{ant-prefix}-cascader-picker:last-child .@{ant-prefix}-input,
+ & > .@{ant-prefix}-cascader-picker-focused:last-child .@{ant-prefix}-input,
  & > .@{ant-prefix}-mention-wrapper:last-child .@{ant-prefix}-mention-editor,
  & > .@{ant-prefix}-time-picker:last-child .@{ant-prefix}-time-picker-input {
  border-top-right-radius: @border-radius-base;
  border-bottom-right-radius: @border-radius-base;
  border-right-width: 1px;
+ border-right-color: @input-border-color;
+ &:hover {
+ .hover();
+ }
+ &:focus {
+ .active();
+ .@{ant-prefix}-cascader-input {
+ .active();
+ }
+ }
  }
  }
 }