Twenty Twenty-One: Add b and strong elements to editor styles.

Sets `font-weight: 700` for these elements in the editor, in order to match the front end styles. It overrides the default admin `font-weight` of `600` for 
these HTML elements.

Props nkeller15, audrasjb, sabernhardt, pavanpatil1, iamfarhan09, poena.
Fixes #58383.




git-svn-id: https://develop.svn.wordpress.org/trunk@56172 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-content/themes/twentytwentyone/assets/css/ie-editor.css

@@ -119,6 +119,11 @@
 	}
 }
 
+b,
+strong {
+	font-weight: 700;
+}
+
 blockquote {
 	padding: 0;
 	position: relative;

src/wp-content/themes/twentytwentyone/assets/css/style-editor.css

@@ -302,6 +302,11 @@
 	}
 }
 
+b,
+strong {
+	font-weight: 700;
+}
+
 blockquote {
 	padding: 0;
 	position: relative;

src/wp-content/themes/twentytwentyone/assets/sass/style-editor.scss

@@ -9,6 +9,12 @@
 
 @import "03-generic/breakpoints";
 
+// Add relevant styles from "04-elements/misc"
+b,
+strong {
+    font-weight: 700;
+}
+
 @import "04-elements/blockquote";
 @import "04-elements/media";
 @import "04-elements/forms-editor";