Update text-spacing with editorial improvements (#4038)

Replaces #3877, which had a lot of merge conflicts.

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Co-authored-by: Kenneth G. Franqueiro <kfranqueiro@users.noreply.github.com>

understanding/21/text-spacing.html

@@ -65,15 +65,15 @@ <h4 id="cutoff">Text Cut Off</h4>
           <figcaption>Vertical text cut off is a failure.</figcaption>
           <img src="img/spacing_cutoff_fail_vertical.png" alt="Heading text truncated vertically." width="420" height="190" />         
         </figure>
-        <p>In Figure 2 the last portion of text is cut off in 3 side-by-side  headings. The 1st heading should read &quot;A cog in the wheel.&quot; But it reads &quot;A cog in the whe&quot;. Only half of the second &quot;e&quot; is visible and the letter &quot;l&quot; is completely missing. The  2nd heading should read &quot;A penny for your thoughts&quot;. But it reads &quot;A penny for your&quot;. The 3rd should read &quot;Back to the drawing board.&quot; But it reads &quot;Back to the drawi&quot;. </p>
+        <p>In Figure 2 the last portion of text is cut off in three side-by-side headings. The first heading should read &quot;A cog in the wheel&quot;, but it reads &quot;A cog in the whe&quot;. Only half of the second &quot;e&quot; is visible and the letter &quot;l&quot; is completely missing. The second heading should read &quot;A penny for your thoughts&quot;. But it reads &quot;A penny for your&quot;. The third should read &quot;Back to the drawing board.&quot; But it reads &quot;Back to the drawi&quot;. </p>
         <figure id="figure-horiz-text-cut">
           <figcaption>Horizontal text cut off is a failure.</figcaption>
           <img src="img/spacing_cutoff_fail_horizontal.png" alt="3 side-by-side headings with truncated text." width="509" height="184" />
         </figure>
       </section>
       <section>
         <h4 id="overlap">Text Overlap</h4>
-        <p>In Figure 3 the last 3 words &quot;Groups and Programs&quot; of the heading "Technologists Seeking Input from Groups and Programs" overlap the following sentence. That sentence should read, &quot;You are invited to share  ideas and areas of interest related to the  integration of technology from a group or program perspective.&quot; But the words &quot;You are invited to share  ideas&quot; are obscured and unreadable.</p>
+        <p>In Figure 3 the last three words &quot;Groups and Programs&quot; of the heading "Technologists Seeking Input from Groups and Programs" overlap the following sentence. That sentence should read, &quot;You are invited to share ideas and areas of interest related to the integration of technology from a group or program perspective.&quot; However, the words &quot;You are invited to share ideas&quot; are obscured and unreadable.</p>
         <figure id="figure-overlapping-text">
           <figcaption>Overlapping text is a failure.</figcaption>
           <img src="img/spacing_overlap_fail.png" alt="Heading text overlaps part of paragraph text." width="510" height="170" />            
@@ -115,15 +115,15 @@ <h4 id="lang">Languages and Scripts</h4>
         <h4 id="results">Results</h4>
         <p id="langimpact">No adverse effects occurred. The following are the specific findings:</p>
         <dl>
-          <dt>Character Spacing </dt>
+          <dt>Character Spacing</dt>
           <dd>Individual characters in words remained intact though they were spaced a bit further apart.</dd>
-          <dt>Word Spacing </dt>
-          <dd>Words were spaced farther apart. In languages that do not have words (e.g. Japanese) applying word spacing had no effect. This is expected.</dd>
+          <dt>Word Spacing</dt>
+          <dd>Words were spaced further apart. In languages that do not have words (e.g., Japanese) applying word spacing had no effect. This is expected.</dd>
           <dt>Line Height</dt>
           <dd>Changing line height did not separate diacritics from characters, nor did it adversely impact ascenders or descenders.</dd>
         </dl>
         <p>As previously discussed, the ability to read text with adjusted spacing is a user responsibility. This is true no matter the language.</p>
-        <p>The SC's exception addresses cases where a text style property is not used in a language or script. In such cases, authors are only required  to ensure  relevant  properties do not break the layout.</p>
+        <p>The SC's exception addresses cases where a text style property is not used in a language or script. In such cases, authors are only required to ensure relevant properties do not break the layout.</p>
       </section>
     </section>
     <section>