Documentation cleanup (#612)

* Added the `@Deprecated` tag to instances where is was mentioned in documentation, but not for the actual code itself.

Changed one documentation link pointing at a non-existing item.

* As per PR suggestion.

(cherry picked from commit 196081a317)

common/common-lang/src/main/java/com/twelvemonkeys/lang/StringUtil.java

@@ -770,6 +770,7 @@ public final class StringUtil {
      */
 
     /*public*/
+    @Deprecated
     static String formatNumber(long pNum, int pLen) throws IllegalArgumentException {
         StringBuilder result = new StringBuilder();
 
@@ -1464,6 +1465,7 @@ public final class StringUtil {
      */
 
     /*public*/
+    @Deprecated
     static String removeSubstring(final String pSource, final char pBeginBoundaryChar, final char pEndBoundaryChar, final int pOffset) {
         StringBuilder filteredString = new StringBuilder();
         boolean insideDemarcatedArea = false;