Rename hshp to `hshp_interp`

Improve clarity. The corresponding actual argument in `eddy_graph` is
`hshp_interp`.

overlap.f90

@@ -5,7 +5,7 @@ module overlap_m
 contains
 
   subroutine overlap(flow, unit_edgelist, nlon, nlat, periodic, dist_lim, &
-       hshp, k, delta, j)
+       hshp_interp, k, delta, j)
 
     ! This procedure finds edges between flow(j - delta) and flow(j),
     ! corresponding to dates k - delta and k. It calls write_overlap
@@ -35,7 +35,7 @@ contains
     ! the extremum of a given eddy.
 
     ! Triplet of shapefiles to which any interpolated eddy will be written:
-    TYPE(shp_tr), intent(in):: hshp
+    TYPE(shp_tr), intent(in):: hshp_interp
 
     integer, intent(in):: k ! date index
     integer, intent(in):: delta ! between 1 and max_delta
@@ -123,8 +123,8 @@ contains
                    flow(j - delta + 1:j - 1)%number_eddies &
                         = flow(j - delta + 1:j - 1)%number_eddies + 1
 
-                   call write_overlap(hshp, unit_edgelist, k, delta, i1, i2, &
-                        m, flow(j - delta + 1:j - 1)%number_eddies, &
+                   call write_overlap(hshp_interp, unit_edgelist, k, delta, &
+                        i1, i2, m, flow(j - delta + 1:j - 1)%number_eddies, &
                         flow(j - delta)%list_vis(i1)%cyclone, &
                         flow(j - delta)%list_vis(i1)%coord_extr, &
                         flow(j - delta)%list_vis(i1)%ssh_extr, &

write_overlap.f90

@@ -9,7 +9,7 @@ module write_overlap_m
 
 contains
 
-  subroutine write_overlap(hshp, unit_edgelist, k, delta, i1, i2, m, &
+  subroutine write_overlap(hshp_interp, unit_edgelist, k, delta, i1, i2, m, &
        i_interp, cyclone, coord_extr_1, ssh_extr_1, coord_extr_2, ssh_extr_2, w)
 
     ! Writes edges to unit_edgelist and interpolated eddies to
@@ -21,7 +21,7 @@ contains
     use derived_types, only: shp_tr
     use write_eddy_m, only: write_eddy
 
-    TYPE(shp_tr), intent(in):: hshp
+    TYPE(shp_tr), intent(in):: hshp_interp
     integer, intent(in):: unit_edgelist ! logical unit for edgelist file
     integer, intent(in):: k ! date index
     integer, intent(in):: delta, i1, i2, m
@@ -64,7 +64,7 @@ contains
        e%ssh_extr = (1 - w_interp) * ssh_extr_1 + w_interp * ssh_extr_2
 
        k_interp = k - delta + j_interp
-       call write_eddy(e, hshp, k_interp, i_interp(j_interp))
+       call write_eddy(e, hshp_interp, k_interp, i_interp(j_interp))
        write(unit_edgelist, fmt = *) k_interp - 1, i_pred, k_interp, &
             i_interp(j_interp), w
        i_pred = i_interp(j_interp)