Fixup usage

src/main/scala/com/fulcrumgenomics/umi/GroupReadsByUmi.scala

@@ -439,20 +439,11 @@ object Strategy extends FgBioEnum[Strategy] {
     |   3. The assigned UMI tag
     |   4. Read Name
     |
-    |Reads are aggressively filtered out so that only high quality reads/mappings are taken forward. Single-end
-    |reads must have mapping quality >= `min-map-q`.  Paired-end reads must both have mapping quality >= `min-mapq`
-    |(Note: the `MQ` tag is required on reads with mapped mates). By default, paired-end reads must have both reads
-    |mapped to the same chromosome (to turn off this filter, use `--allow-inter-contig`).
+    |During grouping, reads are filtered out if a) all reads with the same queryname are unmapped, b) any primary
+    |read has mapping quality < `min-map-q` (default=1), or c) the primary mappings for R1 and R1 are on different
+    |chromosomes and `--allow-inter-contig` has been set to false.
     |
-    |This is done with the expectation that the next step is building consensus reads, where
-    |it is undesirable to either:
-    |
-    |   1. Assign reads together that are really from different source molecules
-    |   2. Build two groups from reads that are really from the same molecule
-    |
-    |Errors in mapping reads could lead to both and therefore are minimized.
-    |
-    |Grouping of UMIs is performed by one of three strategies:
+    |Grouping of UMIs is performed by one of four strategies:
     |
     |1. **identity**:  only reads with identical UMI sequences are grouped together. This strategy
     |                  may be useful for evaluating data, but should generally be avoided as it will