pbmnoise, pgmhist, pgmkernel, pgmnoise, pgmramp, pgmtexture: add pages; ppmhist: modify page (#12202)

pages/common/pgmtexture.md

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+# pgmtexture
+
+> Extract textural features from a PGM image.
+> More information: <https://netpbm.sourceforge.net/doc/pgmtexture.html>.
+
+- Extract textural features from a PGM image:
+
+`pgmtexture {{path/to/image.pgm}} > {{path/to/output.pgm}}`
+
+- Specify the distance parameter for the feature extraction algorithm:
+
+`pgmtexture -d {{distance}} {{path/to/image.pgm}} > {{path/to/output.pgm}}`