maint: remove doubled words in comments, e.g., s/to to/to/

maint: remove doubled words in comments, e.g., s/to to/to/

* tests/ls/color-norm: s/to to/to/
* gl/lib/mbsalign.h (mbs_align_t): s/or or/or/
* src/extent-scan.c (extent_scan_read): s/the the/the/
* src/libstdbuf.c: s/the the/the/
* tests/misc/stdbuf: s/on on/on/
* ChangeLog-2005: s/for\n\tfor /for\n\t/