Rename name-access functions to be less confusing

You can't "get function" or "get module" with these functions; just
their *names*.  Also "get" is inconsistent with eg.  sfpi__ls() and
sfpi__key(): the "getting" part is implied.

src/include-bash/sfpi.sh

@@ -122,7 +122,7 @@ sfpi__import() {
     shellfu import "$mod"
 }
 
-sfpi__get_fun() {
+sfpi__funname() {
     #
     # Print name of plugin $1 function $2
     #
@@ -132,7 +132,7 @@ sfpi__get_fun() {
     echo "${SFPI__PREFIX}_${plg}__$fun"
 }
 
-sfpi__get_mod() {
+sfpi__modname() {
     #
     # Print name of module implementing plugin $1
     #

tests/shellfu_api/oracle/functions.stdout

@@ -93,11 +93,11 @@ sfdoc:sfdoc__ls
 sfdoc:sfdoc__ls_m
 sfpi:__sfpi__ckpfx
 sfpi:sfpi__call
-sfpi:sfpi__get_fun
-sfpi:sfpi__get_mod
+sfpi:sfpi__funname
 sfpi:sfpi__has
 sfpi:sfpi__import
 sfpi:sfpi__is_compat
 sfpi:sfpi__key
 sfpi:sfpi__ls
 sfpi:sfpi__ls_all
+sfpi:sfpi__modname