centrality: Fix simple doc inconsistency

6 jobs for master in 365 minutes and 17 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #3822
amd64
job_clang_amd64

05:09:21

failed #3826
amd64
job_clang_amd64_nosh

05:10:08

failed #3824
amd64
job_clang_py2_amd64

05:21:00

failed #3821
amd64
job_gcc_amd64

05:42:52

failed #3825
amd64
job_gcc_amd64_nosh

05:17:14

failed #3823
amd64
job_gcc_py2_amd64

06:05:15

 
Name Stage Failure
failed
job_gcc_py2_amd64 Test

Doctest summary
===============
1063 tests
4 failures in tests
0 failures in setup code
0 failures in cleanup code
build finished with problems, 27 warnings.
ERROR: Job failed: exit status 1
failed
job_gcc_amd64 Test
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (52) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (54) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (56) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (55) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
ERROR: Job failed: exit status 1
failed
job_clang_py2_amd64 Test

Doctest summary
===============
1020 tests
1 failure in tests
0 failures in setup code
0 failures in cleanup code
build finished with problems, 27 warnings.
ERROR: Job failed: exit status 1
failed
job_gcc_amd64_nosh Test
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (86) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (122) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (102) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (112) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
ERROR: Job failed: exit status 1
failed
job_clang_amd64_nosh Test
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (105) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplri8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (110) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplri8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (78) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplri8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (80) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplri8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
ERROR: Job failed: exit status 1
failed
job_clang_amd64 Test
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (112) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (84) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (100) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
/usr/lib/python3.7/site-packages/matplotlib/textpath.py:349: UserWarning: The glyph (69) of font (/usr/share/texmf-dist/fonts/type1/urw/palatino/uplr8a.pfb) cannot be converted with the encoding. Glyph may be wrong
"be wrong" % (glyph, font.fname))
ERROR: Job failed: exit status 1