backport sync: merge mess (#484)

* datum.table: added SIRGAS 1995 (#464)

Fixes #452

* vdigit: fix testing empty input (#469)

* v.edit: -t => -b in the manual (#471)

* v.generalize: remove_small was removed in https://lists.osgeo.org/pipermail/grass-commit/2011-January/015843.html (#473)

Co-authored-by: Anna Petrasova <kratochanna@gmail.com>
Co-authored-by: Huidae Cho <grass4u@gmail.com>

gui/wxpython/dbmgr/dialogs.py

@@ -248,7 +248,7 @@ class DisplayAttributesDialog(wx.Dialog):
 
                     if newvalue != value:
                         updatedColumns.append(name)
-                        if not newvalue:
+                        if newvalue == '':
                             updatedValues.append('NULL')
                         else:
                             if ctype != str:

lib/gis/datum.table

@@ -99,3 +99,5 @@ itrf92   "ITRF92"    grs80 dx=0   dy=0    dz=0
 S_JTSK	"System_Jednotne_Trigonometricke_Site_Katastralni"	bessel	dx=589	dy=76	dz=480
 # http://spatialreference.org/ref/epsg/4674/
 sirgas2000 "Sistema_de_Referencia_Geocentrico_para_las_AmericaS_2000"   grs80       dx=0        dy=0       dz=0
+# https://epsg.io/4170, sirgas1995 in degree
+sirgas1995 "Sistema_de_Referencia_Geocentrico_para_las_AmericaS_1995"   grs80       dx=0        dy=0       dz=0

vector/v.edit/v.edit.html

@@ -31,7 +31,7 @@ covered by two bounding boxes (center at 599505,4921010 and
 
 <h2>NOTES</h2>
 
-If no vector features are selected or the flag <b>-t</b> is
+If no vector features are selected or the flag <b>-b</b> is
 used, topology is not build at the end.
 
 <h2>USAGE</h2>

vector/v.generalize/v.generalize.html

@@ -59,7 +59,6 @@ would cause a lower degree of simplification.
 <li>Lang Algorithm</li>
 <li>Vertex Reduction</li>
 <li>Reumann-Witkam Algorithm</li>
-<li>Remove Small Lines/Areas</li>
 </ul>
 
 Different algorithms require different parameters, but all the algorithms