v5: Drop remaining deprecated mixins (#28461)

- Deletes mixin mentions from float docs
- Deletes mixin mention from visibility docs
- Deletes the image-replacement page for text-hide

scss/mixins/_float.scss

@@ -1,14 +0,0 @@
-// stylelint-disable declaration-no-important
-
-@mixin float-left {
-  float: left !important;
-  @include deprecate("The `float-left` mixin", "v4.3.0", "v5");
-}
-@mixin float-right {
-  float: right !important;
-  @include deprecate("The `float-right` mixin", "v4.3.0", "v5");
-}
-@mixin float-none {
-  float: none !important;
-  @include deprecate("The `float-none` mixin", "v4.3.0", "v5");
-}

scss/mixins/_text-hide.scss

@@ -1,11 +0,0 @@
-// CSS image replacement
-@mixin text-hide($ignore-warning: false) {
-  // stylelint-disable-next-line font-family-no-missing-generic-family-keyword
-  font: 0/0 a;
-  color: transparent;
-  text-shadow: none;
-  background-color: transparent;
-  border: 0;
-
-  @include deprecate("`text-hide()`", "v4.1.0", "v5", $ignore-warning);
-}

scss/mixins/_visibility.scss

@@ -1,8 +0,0 @@
-// stylelint-disable declaration-no-important
-
-// Visibility
-
-@mixin invisible($visibility) {
-  visibility: $visibility !important;
-  @include deprecate("`invisible()`", "v4.3.0", "v5");
-}