Update documentation.

Update the documentation about the bridges and the composite ontologies
to reflect the fact that bridging equivalence axioms now use the 'in
taxon' relation, rather than 'part of'.

docs/bridges.md

@@ -8,14 +8,14 @@ Uberon term and a term from the foreign ontology.
 For example, the `uberon-bridge-to-zfa` bridge contains axioms such as
 this one:
 
-> ZFA:0001262 EquivalentTo: UBERON:0005564 and (BFO:0000050 some NCBITaxon:7954)
+> ZFA:0001262 EquivalentTo: UBERON:0005564 and (RO:0002162 some NCBITaxon:7954)
 
 which states that ZFA’s [gonad
 primordium](http://purl.obolibrary.org/obo/ZFA_0001262) (ZFA:0001262) is
 equivalent to a Uberon’s [gonad
 primordium](http://purl.obolibrary.org/obo/UBERON_0005564)
-(UBERON:0005564) that is [part
-of](http://purl.obolibrary.org/obo/BFO_0000050) a
+(UBERON:0005564) that is [in
+taxon](http://purl.obolibrary.org/obo/RO_0002162) some
 [Danio](http://purl.obolibrary.org/obo/NCBITaxon_7954) (NCBITaxon:7954).
 
 Such a bridge may be used by anyone who wants to merge Uberon and ZFA to

docs/combined_multispecies.md

@@ -113,7 +113,7 @@ that `collected-drosophila` contains the following axiom (provided by the
 bridge between Uberon and FBbt):
 
 ```
-FBbt:00004865 EquivalentTo: UBERON:0000992 and (part_of some NCBITaxon:7227)
+FBbt:00004865 EquivalentTo: UBERON:0000992 and (in_taxon some NCBITaxon:7227)
 ```
 
 (`NCBITaxon:7227` being the identifier for the _Drosophila melanogaster_
@@ -132,7 +132,7 @@ FBbt:00004911 SubClassOf: continuous_with some FBbt:00004865
 gets rewritten as
 
 ```
-FBbt:00004911 SubClassOf: continous_with some (UBERON:00009992 and (part_of some NCBITaxon:7227))
+FBbt:00004911 SubClassOf: continous_with some (UBERON:00009992 and (in_taxon some NCBITaxon:7227))
 ```
 
 The figure below illustrates the resulting differences between a