doc: Fix most Flake8 issues in example files (#4353)

This addresses F403 and F405. These are mostly related to wild card imports. This does not touch max line length issue with long tool description documentation line (current format limitation).

.flake8

@@ -22,9 +22,7 @@ per-file-ignores =
     __init__.py: F401, F403
     man/build_html.py: E501
     imagery/i.atcorr/create_iwave.py: F632, F821, W293
-    doc/python/raster_example_ctypes.py: F403, F405
-    doc/python/vector_example_ctypes.py: F403, F405
-    doc/python/m.distance.py: F403, F405, E501
+    doc/python/m.distance.py: E501
     doc/gui/wxpython/example/dialogs.py: F401
     locale/grass_po_stats.py: E122, E128, E231, E401, E722
     gui/scripts/d.wms.py: E501

doc/python/m.distance.py

@@ -45,10 +45,21 @@
 # %end
 
 import sys
+from ctypes import byref, c_double
 
 import grass.script as gs
-
-from grass.lib.gis import *
+from grass.lib.gis import (
+    G_gisinit,
+    G_begin_distance_calculations,
+    G_scan_easting,
+    G_scan_northing,
+    G_distance,
+    G_begin_polygon_area_calculations,
+    G_area_of_polygon,
+    G_database_units_to_meters_factor,
+    G_database_unit_name,
+    PROJECTION_LL,
+)
 
 
 def main():

doc/python/raster_example_ctypes.py

@@ -17,9 +17,23 @@
 
 import os
 import sys
-
-from grass.lib.gis import *
-from grass.lib.raster import *
+import math
+
+from ctypes import POINTER, c_int, c_float, c_double, c_void_p, cast
+
+from grass.lib.gis import G_gisinit, G_find_raster2, G_free
+from grass.lib.raster import (
+    Rast_map_type,
+    CELL_TYPE,
+    FCELL_TYPE,
+    DCELL_TYPE,
+    Rast_open_old,
+    Rast_allocate_buf,
+    Rast_window_rows,
+    Rast_window_cols,
+    Rast_get_row,
+    Rast_close,
+)
 
 # check if GRASS is running or not
 if "GISBASE" not in os.environ:

doc/python/vector_example_ctypes.py

@@ -7,9 +7,28 @@
 
 import os
 import sys
+from ctypes import pointer, byref
 
-from grass.lib.gis import *
-from grass.lib.vector import *
+# Import specific functions and classes instead of using wildcard imports
+from grass.lib.gis import G_gisinit, G_find_vector2
+from grass.lib.vector import (
+    Map_info,
+    Vect_set_open_level,
+    Vect_open_old,
+    Vect_get_full_name,
+    Vect_is_3d,
+    Vect_get_num_dblinks,
+    Vect_get_scale,
+    Vect_get_map_box,
+    Vect_point_in_box,
+    Vect_get_num_lines,
+    Vect_get_num_primitives,
+    Vect_get_num_areas,
+    Vect_close,
+    bound_box,
+    GV_POINT,
+    GV_LINE,
+)
 
 if "GISBASE" not in os.environ:
     sys.exit("You must be in GRASS GIS to run this program.")