javadoc edit

src/main/java/gov/usgs/earthquake/nshmp/gmm/ChapmanGuo_2021.java

@@ -23,7 +23,7 @@ import com.google.common.io.Resources;
  * ratio model to account for amplification and attenuation effects in the
  * Atlantic and Gulf coastal plain: Bulletin of the Seismological Society of
  * America, v. 111, n. 4, p. 1849-1867, doi: <a
- * href="https://doi.org/10.1785/0120200322"> 10.1785/0120200322</a>.
+ * href="https://doi.org/10.1785/0120200322">10.1785/0120200322</a>.
  *
  * @author U.S. Geological Survey
  */