add more display_as to _data python, r and js are now all covered

Author: michaelbabyn

_data/display_as.yml

@@ -1,3 +1,15 @@
+mathematics:
+    reference: '#mathematics'
+    text: Mathematics
+statistics:
+    reference: '#statistics'
+    text: Statistics
+peak-analysis:
+    reference: '#peak-analysis'
+    text: Peak Analysis
+signal-analysis:
+    reference: '#signal-analysis'
+    text: Signal Analysis
 file_settings:
     reference: '#fundamentals'
     text: Plotly Fundamentals