Rename html/ directory to docs/ for GitHub Pages compatibility.

To ensure compatibility with GitHub Pages, this commit renames
the html/ directory to docs/. This change is necessary because
GitHub Pages uses the docs/ directory as a default location for
serving web pages. By renaming the directory, the project's
documentation will be accessible on the web when published to
GitHub Pages.

diff --git a/html/index.html b/docs/index.html
similarity index 100%
rename from html/index.html
rename to docs/index.html

diff --git a/html/index_en.html b/docs/index_en.html
similarity index 100%
rename from html/index_en.html
rename to docs/index_en.html

diff --git a/html/pg_bigm-1-1.html b/docs/pg_bigm-1-1.html
similarity index 100%
rename from html/pg_bigm-1-1.html
rename to docs/pg_bigm-1-1.html

diff --git a/html/pg_bigm-1-2.html b/docs/pg_bigm-1-2.html
similarity index 100%
rename from html/pg_bigm-1-2.html
rename to docs/pg_bigm-1-2.html

diff --git a/html/pg_bigm.html b/docs/pg_bigm.html
similarity index 100%
rename from html/pg_bigm.html
rename to docs/pg_bigm.html

diff --git a/html/pg_bigm_en-1-1.html b/docs/pg_bigm_en-1-1.html
similarity index 100%
rename from html/pg_bigm_en-1-1.html
rename to docs/pg_bigm_en-1-1.html

diff --git a/html/pg_bigm_en-1-2.html b/docs/pg_bigm_en-1-2.html
similarity index 100%
rename from html/pg_bigm_en-1-2.html
rename to docs/pg_bigm_en-1-2.html

diff --git a/html/pg_bigm_en.html b/docs/pg_bigm_en.html
similarity index 100%
rename from html/pg_bigm_en.html
rename to docs/pg_bigm_en.html

diff --git a/html/release-1-0.html b/docs/release-1-0.html
similarity index 100%
rename from html/release-1-0.html
rename to docs/release-1-0.html

diff --git a/html/release-1-0_en.html b/docs/release-1-0_en.html
similarity index 100%
rename from html/release-1-0_en.html
rename to docs/release-1-0_en.html

diff --git a/html/release-1-1.html b/docs/release-1-1.html
similarity index 100%
rename from html/release-1-1.html
rename to docs/release-1-1.html

diff --git a/html/release-1-1_en.html b/docs/release-1-1_en.html
similarity index 100%
rename from html/release-1-1_en.html
rename to docs/release-1-1_en.html

diff --git a/html/release-1-2.html b/docs/release-1-2.html
similarity index 100%
rename from html/release-1-2.html
rename to docs/release-1-2.html

diff --git a/html/release-1-2_en.html b/docs/release-1-2_en.html
similarity index 100%
rename from html/release-1-2_en.html
rename to docs/release-1-2_en.html

diff --git a/html/style.css b/docs/style.css
similarity index 100%
rename from html/style.css
rename to docs/style.css