Fix migration guide typos (#36040)

* Correct font-weight semibold utility class name

* Tiny sentence correction

site/content/docs/5.1/migration.md

@@ -17,7 +17,7 @@ Bootstrap v5.2.0 features a subtle design update for a handful of components and
 
 ### New `_maps.scss`
 
-**Bootstrap v5.2.0 introduced a new Sass file with `_maps.scss`.** It pulls out several Sass maps from `_variables.scss` to fix an issue where updates to an original map were not applied to secondary maps that extend them. For example, updates to `$theme-colors` were not being applied to other theme maps that relied on `$theme-colors`, breaking key customization workflows. In short, Sass has a limitation where once a default variable or map has been _used_, it cannot be updated. _Similarly, there's a similar shortcoming with CSS variables when they're used to compose other CSS variables._
+**Bootstrap v5.2.0 introduced a new Sass file with `_maps.scss`.** It pulls out several Sass maps from `_variables.scss` to fix an issue where updates to an original map were not applied to secondary maps that extend them. For example, updates to `$theme-colors` were not being applied to other theme maps that relied on `$theme-colors`, breaking key customization workflows. In short, Sass has a limitation where once a default variable or map has been _used_, it cannot be updated. _There's a similar shortcoming with CSS variables when they're used to compose other CSS variables._
 
 This is why variable customizations in Bootstrap have to come after `@import "functions"`, but before `@import "variables"` and the rest of our import stack. The same applies to Sass maps—you must override the defaults before the defaults get used. The following maps have been moved to the new `_maps.scss`:
 
@@ -61,7 +61,7 @@ Your custom Bootstrap CSS builds should now look something like this with a sepa
 
 ### New utilities
 
-- Expanded [`font-weight` utilities]({{< docsref "/utilities/text#font-weight-and-italics" >}}) to include `.fw-600` for semibold fonts.
+- Expanded [`font-weight` utilities]({{< docsref "/utilities/text#font-weight-and-italics" >}}) to include `.fw-semibold` for semibold fonts.
 - Expanded [`border-radius` utilities]({{< docsref "/utilities/borders#sizes" >}}) to include two new sizes, `.rounded-4` and `.rounded-5`, for more options.
 
 ### Additional changes